You want a car stereo that will allow you to plug a cable from the mp3 player or ipod headphone jack to play your fave music.
You'll see the input hole on the stereo. Price? well whats your budget?
£140+ and you'll get a CD player built in with the option of a cd autochanger in the boot in future.
See Halfords I guess. (You might need wiring and fitting and facia covers)
Bluetooth ear piece for your moby? again budget? and look at battery lifespans etc and charging in your car.
Personally I would get a hands free kit for your car that charges your mobile and sticks the sound through your car speakers.
Personally go into Halfords get a quote, then see an idependant audio store that will fit everything.
All about how much cash you want to spend, no budget? then get decent kit and make sure your car insurance covers your stereo, mp3 unit and handsfree kit.