09 radio in an 05 aux input cable

I recently purchased a 2009 factory radio to put into my 2005. I hooked it up and the radio works fine, the only problem I am having is hooking up an aux input to the radio. My local stereo store did not have a cable that would hook up to a factory toyota radio and I cannot find one online.
Are there any stores that sell a cable to hook up an aux input that plugs into the factory radio? Or am i forced to ask the stealership for help?