Not to worry mate. I did this just two days ago with my Riva tnt2 card. Look on the page for a link to NVchooser. Once you download that, you need to do two things to it.
1) run this command : dos2unix NVchooser.sh
This will get rid of all of the formatting done by windows.
2) next do this: chmod +x NVchooser.sh
this will make it execuatable.
now just ./NVchooser.sh
This will then analyze your system and tell you what you need. The rpm install is fairly painless. Just download and install the rpms (DO THIS IN TEXT MODE, NOT IN XWINDOWS!!) Use rpm -ivh rpmnamehere to install an rpm in text mode (or cli as it is known).
Also follow the readme!! You have to modify part of your X11config-4 file to get it to work. Good luck and drop me a line if you have any problems.