I don't believe your problem is related to your video card, rather q3a itself.
It looks like your user interface is mismatched somehow. Bad install on a patch or possibly using some third party program like arenaspy.
You may be able to correct it pretty easily by reinstalling the latest q3a patch (version 1.30 I believe). Otherwise save your q3config file and then reinstall quake, patch it and put your config file back. If you need any more help on this issue, I'd recommend visiting the forums on www.quake3world.com for some help rather than Toms (for this issue anyway)