I would update your kernel to the new Voodoo kernel before starting...
Use AMD Patcher to patch single updates that you can download right from Apple's Download site. Then before updating (in order of course) you need to make backups of your kernel extensions and also ensure you have the proper kexts and other files necessary to update (check the update threads in this forum for help and a listing of these files). Then run each and make sure you reboot a few times to ensure each update works and don't worry about your sound or video not being exactly the way you had it set up until you are fully updated.

---