thank you, everybody. I love this forum and am really appreciative of all of the help you all have given me. 
For the prices that the dealer is quoting, it sounds like they intend to change the whole cooling system (radiator, water pump, thermostat, all hoses)
If the leak is at a seam, it probably wonāt fail catastrophically. You can probably drive it for a little while if you donāt mind the mess and you keep a close eye on your water level. Does the cap go on the radiator or on the external reservoir? If you cannot see into the radiator, remember that a full reservoir does NOT mean a full radiator.
I would not worry about a long guarantee on a replacement radiator, but if that is important to you and the cost differential is not too great, go for it.
I just looked at an on-line parts house that I trust to sell quality parts.
Radiator $75-$100
Hoses $10-$15 each (the top one fails first)
Thermostat $10-20 (donāt forget to buy the gasket)
1 Gal Antifreeze $5-$10
This is not difficult to do. If your friend will help you, you can resolve this issue for less than $200 including tax and shipping, plus the cost of dinner for your friend.
One correction to another post - someone said that the car would run hotter with pure water instead of water/coolant mix. This is inaccurate. Water has a higher specific heat than water/coolant. The car will run the same temperature or cooler with pure water. However, if it gets excessively hot for any reason, it will boil at a lower temperature with pure water, and pure water offers no corrosion protection.
For the prices that the dealer is quoting, it sounds like they intend to change the whole cooling system (radiator, water pump, thermostat, all hoses)
I doubt it. That is how much I was quoted for the installation of a new radiator and two radiator hoses on my Civic, which is why I did the replacement myself.
This car has the radiator beside the air conditioning condenser (instead of one in front of the other), so changing it is more labor intensive than changing most radiators.
If the OP wants to try to tackle this job, I suggest she first buy a manual to see what she is getting into. This isnāt just a simple radiator swap.
I am trying to get this all sorted out and someone will take a look at my car today. Is a new thermostat necessary? How long does it usually take to replace a radiator?
You might consider adding the thermostat to the job if it doesnāt cost much, but I wouldnāt replace it unless it is malfunctioning.
The radiator job should take no more than a few hours, but it isnāt as easy as most radiator swaps.
I am definitely not able to do it myself (donāt even know how to change my own oilā¦). I donāt have air conditioning in my carā¦will that make the radiator change any easier?
You might check a radiator shop. They will be able to fix your car at least as good as auto repair shop and in my experience, for less money. They even rebuilt some radiators when possible, so maybe your is a candidate for a rebuild or repair. Iām not familar with whatās possible with a plastic and copper (or alum) rad.
In these economic times a moonlighting mechanic should be able to do this for between $200 and $250. Keep an eye on the temp gauge. Keep the coolant full. And keep the trips short.
Stop leak is an option and a cheap one at that. If it works great. If not, when you change the radiator the coolant should be flushed. The coolant gets drained anyway when the radiator is changed so its not that big of a deal.
Online pricing shows that $110 for parts should be attainable with lifetime warranties on the radiator. A DIY site lists labor time as 3.5 hours so an experienced mechanic should be able to do it in about 60-75 minutes. Book time is probably about 2 hours.
Finally, find a good mechanic that you can trust and know to be fair. Then when you have to get something fixed it isnāt so stressful. The money will still be tight but a least you donāt have to worry about getting cheated.
I donāt know without seeing the engine compartment.
I havenāt seen anyone mention using distilled water or at least filtered water, not to mentionā¦
donāt let cats drink all of this coolant that you have been leaking. The cats sense of smell is part of their taste buds systemā¦ much more sensitive than ours.They love the smell of antifreeze. They die from the antifreeze.
If you have coolant problems the salts from tap water could clog up those tiny coolant passages in that little engine every time the water evaporates depending on your quality of tap water.
You might be able to show everyone here a picture of the leak if you āAttach Fileā of a digital photo as the engine is running. This site seems to be able to attach some kind of file to this discussion. I have never tried it though. The āAttach Fileā option seems to only be visible when you are āReplyingā to the message board ā¦ on the left bottom of the input window.
DO NOT DELAY ā¦ radiator could deteriorate rapidly putting your engine at risk! WATCH YOUR TEMPERATURE GAUGE VERY CAREFULLY!!!
Honda radiator can NOT be reliably repaired according to ALL of my sources.
New radiator from parts store should be less than $100. Hoses/thermostat your option. Forget water pump ā¦ it is driven by timing belt ā¦ you DO NOT want to do that. But DO replace water pump when doing timing belt.
*** CAUTION ***: If your Civic is an automatic transmission, go to bottom of this post FIRST!!!
The entire radiator change can be done without getting under the Civic provided the lower hose can be disconnected from the top!
Drain radiator (wing bolt at bottom of radiator toward engine, opens counter-clockwise), disconnect overflow hose at mouth/top of radiator. Follow instruction on antifreeze container for handling and disposal of old coolant.
Check coolant for cleanliness and oil. Oil would suggest an engine problem (an entirely different issue).
There may be part of the air intake directly behind the overflow reservoir ā¦ if so remove air intake by pulling STRAIGHT UP and set it to the side.
Then pull the overflow reservoir STRAIGHT UP and set it to the side.
Unplug fan connector left side of radiator (part of the connector is permanently attached to fan housing).
Disconnect upper & lower radiator hoses at radiator (could be done at other end but probably more difficult).
Remove the ONE (1) bolt from metal bracket holding down the top center of the radiatiator to the āinside upper cross member at the front of the engine compartmentā. Lift radiator straight up and radiator with fan and fan housing should be out.
Two (2) posts on bottom of radiator holds the bottom of radiator in place. Save and re-instal the 2 grommets from these 2 posts back onto the two round metal āreceiversā on the ābottom cross memberā.
Flush fresh water through upper radiator hose.
Remove 4 screws holding fan housing to radiator. Remove fan housing and re-install on new radiator.
Simply reverse the proceedure.
[If automatic RE-connect 2 transmission fluid lines BEFORE ADDING FLUID!]
Add 50/50 antifreeze mix (including overflow reservior), start engine check fluid level and add AS necessary. Raise engine speed several times to clear air bubbles adding fluid as needed.
When engine is up to operating temperature, cap the radiator and run until fan turns on.
CAUTION THINGS ARE NOW HOT! Raise engine speed several times to clear any remaining air bubbles. Again add fluid as needed USING EXTREME CAUTION!
Check for leaks!!!
Should be good to go in less than 1 hour (maybe even as little as 30 minutes) thanks to outstanding Honda packaging!
*** CAUTION ***: If automatic transmission *** AFTER draining antifreeze *** there are two (2) transmission fluid lines going to the lower tank of the radiator on the engine side of radiator. Disconnect them and cover with plastic wrap. Reinstall just BEFORE adding NEW coolant to radiator.
Hope this helps.