I agree with you that that little light is not the best. I haven't changed anything myself but it shouldn't be any problem. Just find another light that you like and mount it in your trunk. Then, remove the stock light and connect new wires to the stock wire. (I don't know what it looks like here in my office, so I can't give you a more precise description). Then run the new wires to your new light and connect.
If you are not so technical (at all ) then talk to any repair shop. They should be able to fix this in 15 minutes.