Audio Systems: 2004 chevy audio, auxiliary input adapter, chevrolet 2002

Question
I have a 2004 Chevy Silverado, the audio system is not working fully. the cd player will not take a cd, it sounds like it is trying but will not load. the tape player says it needs cleaning, i have cleaned it 3 x. it plays a tape but you can hear the other side in quiet parts of the tape.  The dealership says they don't service audio. They will take it out and send to GM. Cost of approx $300-$4oo. I asked, is it possible to upgrade to a audio system that will also accept usb from Iphone?  They weren't sure.  They said it might not match up and interfere with the security system. What are your thoughts.

Answer
try this to use your ipod
http://www.oemautosound.com/pc-296-83-pie-gm12-aux-chevrolet-2002-2007-auxiliary...

or this full controls and ipod text on the radio screen will also work with the steering controls

http://www.oemautosound.com/pc-512-187-pie-ipod-interface-with-auxiliary-input-x...