What kinda paint you after?
If its to patch up the odd scratch or two then Halfords or somewhere like A1 motorspare should stock the colour you need as long as its a factory colour.
If its to respray thewhole car try contacting a few body shops and see if they can point you in the right direction.
Abit vage with the question - the more information you post, the more informatiom people will have to post back