I have a first gen Mac Pro, and the video card is on it's last legs. Scouring the web, it looks like my options for a new video card are few, and expensive. However, it seems as though the kind of video card I can use depends in part on what OS I use, but I could be reading things wrong. I know I need to be able to run OSX enough to be able to get firmware updates, but I'm hoping that if I can get a new card before this one craps out, I can make it a secondary card that I'd only need to use to get on OSX. Again, this is assuming I have any clue what I'm talking about.

Are their other options if I just switch to Ubuntu, or am I stuck? $150< is just not possible for me right now. I do enough on my computer that I need more than just the on-board graphics.