Radio Reception

My 05 grand prix is having bad radio reception. Sometime if i hit a bump it is completly lost signal and will come back as it pleases. it also dosen't receive a signal that is more than 10 miles away very clearly. It just started after i cleaned the rear window (that is where my antenna is). Does anyboby have any suggestions ??

you either nicked the rear defroster grid while cleaning the window or bumped the wires that run from it to the antenna module mounted under the headliner.