DO NOT attempt this. It’s a Mickey Mouse (sorry, Walt) solution to the problem, and your knee is likely to dent the door. There is a correct way to adjust the windows (if they are adjustable), and a service manual for your vehicle will tell you the proper way to do it. The weather strip at the bottom of the window will never be “water tight.” SOME water will always get into the door. That’s why there are drain holes in the bottom of each door on your Prizm. Open the doors and look if you don’t believe me.
If the door drains are clear and functioning, I’ll bet the water on the floor is coming from somewhere other than the side windows.