Lose the steering wheel controls?
Several companies offer "interfaces" that will interconnect between medium to upper end car stereo head units allowing them to function with the original steering wheel mounted controls in many common cars.
CD-players will not play DVD discs.
However there are car stereo units that WILL play DVD discs
loaded with mp3 files and even DVDs on either a flip out screen or
an external monitor.
one particular unit jumps to mind... the MEX-DV2000,
a 2007 model year Sony (still commonly available on ebay) .
this unit will take up to 1000 mp3 files on a DVD-R disc
(Exceed 1000 and it won't display the track title)
You just need to shop around a bit to find a unit that suits your needs/wants AND that you can buy a converter/interface to let
you control the unit with your exsisting controls.