Do you know about deviantART
? From what little I know of it, it's an online art community. Registered members can set up an art gallery and sell their work as prints (handled through deviantArt's print program) and receive a commission. A friend of mine (23 y/o full-time student getting her MFA) has had her account since 2001 and has used it (is still using it) to sell her works. She also has a personal website where she will sell the originals; she also accepts commissions. You might want to try something similiar for awhile and see if you like it. If you like, you can PM me for the link to my friend's site for an example. The good thing about deviantArt is that your work gets exposure to others, which can open up more opportunities for you in the art world (or at least get you connected!). If you do decide to go the deviantArt route, though, you should probably carefully read over Terms of Service (who owns the work, etc).
As for careers that combine programming and art, you could always look into computer graphics-- animation, special effects, games, etc. However, that kind of stuff will usually require knowledge of some 3D graphics engine, like Maya, or Blender. But I know for a fact that Pixar hires "technical artists" and you definitely sound like you fit the bill!