To get the exact colour code for your car, open the drivers side door and you'll see a white strip around the hinge area with details on it
Could be any of the following:
Black -
200R
Black Satin -
229
Black -
EXL
Black Satin -
EXX
Black (onyx) -
EXY
Matt Black -
FXX
Black -
GYA
Halfords is your best bet to buy the paint, but it's always worth checking out eBay first.
Hope this helps!