The Becker sat nav

Hi all. I have bought a V8 D2 as a replacement for the wife it came with a factory fitted Becker sat nav. I borrowed a disk from a guy and fired the system up. I was expecting a bit more than I got ! Its like a 70s arcade game! My mate has a Tom Tom and that puts the Becker into the stone age. I have tried a number of outlets to find a system to replace it. I want to keep the steering wheel controls, and the way it cuts over the music to give directions. Dont mind dumping the CD autochanger, the old lady took all the CDs when she left anyway, and I dont want to alter the dash. Has anybody fitted a system that can do this? I have seen a Tom Tom system onthe web, motorized screen etc. That would look the dogs in my dash, but everybody I ask is vague about it, "Might have to change the speakers" etc. Any ideas ?