01 Vw Jetta Stereo Question

Hi I have a 01 VW Jetta with stock stereo and stock cd changer I want to add a amp and sub but im not sure how to connect them I dont want to lose the cd changer to put auxillary any help would be great i dont know where else to turn:banghead:

Unfortunatly the easiest way to do this and get all the features you want you are going to have to get aftermarket equipment. New head units are pretty inexpensive and the audio quality is far superior to any stock unit.