Sat Nav/mp3 player suggestions for mark 4 Golf 2002?

I have just bought a VW Golf mark 4 and have a large hole without even a radio. I would like to fill it with the VW standard sat nav system but may have problems as I have no CD changer and would rather have mp3 capabilities as well. Does the VW sat nav for this have mp3 capabilities or anyway will I only be able to use the sat nav if I buy a CD changer as well. Is there an alternative manufacturer that ticks these boxes and is also designed to fit neatly into the dash of a mk 4 golf?