Mine was a superchips map but it was already on the car when i got it.

Ballpark figure for a remap are £400 but you may be able to find places that are cheaper as they have open days or special offers on.

The superchips map is a "generic" one (as its not specific to your vehicle, but will still give good gains) but if you go to a proper tuning company like Celtic tuning or AmD essex then they can get the most out of the vehicle (if you've put mods on it), I'll be going to a place like that for my next car once i'm at the stage for exhaust/remap.