Buy a new TomTom or Garmin and forget about the car's system. I don't think you can upgrade an old system with the latest mapping because technology has moved on a long way since the sat nav was designed for your car. I can't point you anywhere except Google and cannot guarantee that anything you find there will be any good. Even if you can find something, it is likely to be 2 - 3 years out of date, which is better than your current mapping probably 10 years out of date. Old systems cannot be updates as fast as TomToms and Garmins.