Jackval, can you post some pictures to give us a better idea of what you are looking at? We all love pictures, and it would possibly reveal a better solution.
I have two compressors:
A small 5 gallon compressor that would be minimally adequate to paint a bumper, running at constant duty. Plugs into a standard household outlet. Cost under $200.
A 60 gallon 240V compressor that easily provides the pressure and volume for painting an entire car. I wired it to plug into the same outlet that is used by a clothes dryer. Cost $500 to $1200.
Your requirements for a compressor will also vary depending on your spray equipment. As others have said, You may be best served by getting a premixed spray can or two from an auto parts store that sells paint or an online vendor such as 'Scratch Wizard'.
Post again since you have a bunch of us interested in the problem, but you may best solve the problem with your three-phase by asking an electrician. I don't doubt that we have a few experts here, but we are more about the cars than how to wire your garage.
