Add aux adapter capability to cd player/stereo?

I have a vehicle with a type 3 cd player without the disc/aux button and without the aux adapter port. Can anyone recommend an inexpensive method to add this option, preferably maintaining the stock stereo appearance? What might be involved with replacing my type 3 with a type 1 or 2 player? I guess I would need the wiring diagram to identify what pin out on the new player would need wiring to an aux jack. I would rather not go the fm modulator route.

 

Tried different search terms and found this
Add Aux to Base Prius via Radio Upgrade | PriusChat