Audio Systems: changing factory stereo in 2005 Cargo Van, chevy express cargo van, wal marts

Question
Hi!  My husband is trying to change the factory stereo in his 2005 Chevy Express Cargo van.  He has bought the faceplate and the antenna booster.  However he is having a very hard time finding the plug that plugs into the factory wire harness.  He stopped at Advance Auto and they said its not available yet.  Wal-Marts book show the part for the 2005 but its not on the shelf.  He also stopped at Circuit City and they said the part is $100.00.  He is installing a Koss CD/radio.  Do you have any suggestions?  Thanks in advance for any help you may be able to give us.  So much for his father's Day gift working on Father's Day.

Answer
circuit city is right about the cable and the cost
he needs to buy  the plug,it is also a module not a simple plug
if he removes the factory radio a lot of things can go wrong in that vehicle
air bag problems, gas cluster,no warnings when there is no fuel, not the correct speed when driving,no key on the ignition or lights on warning,
buy the plug

http://www.oemautosound.com/pc-218-135-pac-c2r-gm24.aspx