You’re welcome.
The specs you gave for the solar panel sound a bit low to do what you want to do. It would be good to know what the current demand is on the battery so the proper size solar panel could be selected. I would guess that you would want something on the order of a couple of watts. That would handle about 200 milliamps of current. Most cars today I think draw between 25 to 35 milliamps of current to keep things alive while the car is parked. Any car will fail after enough time has gone by. A week is a bit short though without a doubt. You may want to consider adding another larger battery to extend the time period. Adding a battery like an Optima would make a big difference in the time period and safe to install in that area.
See if you can find out what the current draw is on your battery while the car is off. See if that meets spec with the factory specs. If you find out what it is let us know what it is. It would be good to know. Perhaps there is something causing excessive draw on the battery. So finding out where things stand is a good first start. The battery capacity may be low also.