A custom bodyshop is usually better, but any bodyshop can repaint your car. Obviously don't go to a cheap run-down shop or to Maco or Sheib.
Also, any shop that paints cars will have access to paint books with color codes. Some automotive supply non-chain stores will also have these books. Over here there's a Spectrum automotive supply store which has pretty much everything from House of Kolors, Lamborghini, and Dupont Hot Hues to "normal" OEM colors like Honda, Geo, Kia, etc.
