Gus, you don't mention what kind of paint you were using. Is it flat or gloss, acrylic or enamel? You'll most likely need another coat or two, and then, after it's cured completely (the curing time will depend on the type of paint), you can buff it, polish it and give it a clear coat, the type of which will depend largely upon the type of finish you're looking for. If you're looking for a bright, shiny finish, you can use a polishing kit and a gloss clear top coat (sprayed, not brushed).
For a killer aluminum finish, you might try bare metal foil, available on-line and at most good model stores.
Glenn