mask it off, sand down with increasingly fine papers to get a smooth finish, prime, smooth again between coats of primer. spray colour layers, again, fine sanding between coats. can get paints from most motor places, get your paint code off the vin plate. finish with a few coats of clear laquer then remove the masking. best to save it for a warm few days, or if you can remove the bits (bumpers etc) for a few days, spray them up in your garage or something. leave them to dry and go off well between coats. should be sorted then.
EDIT: and don't forget to give it a good polish once its all done.