You can buy paint look on the PPG website and look for distributers. I use PPG Acrylic urethane on the model boats. I'm sure you can find the same for Dupont and some of the other car paint makers.
heres another brand that has AWSOME colors but is a littep pricey compared the the PPG.
http://www.houseofkolor.com/hok/index.jsp
The biggest thing I've found when painting is setting the spray pattern so I know howmuch paint I'm putting on the piece and how wet I can make them before they run. Practice with a test piece before you hit you're prize posession.
Also watch the humidity, ambient temperature and dust sources.
You'll want a water trap for your compressor line so you don't get water in the paint as you're spraying.
You will NEED to get a Vaper rated resporator and air tight goggles and latex/nitrile gloves.
Get them whater you get your paints and make sure they are approved for painting. The fumes are very dangerous and should not be taken lightly. Don't just get a sanding mask either, you need a resporator that goes over your nose and mouth and preferably has two canisters rated to capture paint vapors. Expect to pay ~$50 for a proper resporator. Even with this I wouldn't spend more time than necessary in a strong paint fume concentration. Get in, paint and get to fresh air.
Why do I stress that so much? I have nerve damage in my arms and legs that are linked to breathing this stuff. All the doctors thought I was diabetic after the EMG tests. Brought in some paint samples and they agreed that is probably what did it. I had a small paint booth, no ventalation and a sander "cup" mask.
I still paint but am MUCH more careful.
You can get pretty good from off the gun but perfection comes from polishing.