Well, that does assume you are in runlevel 3 already. However, if you boot up into a graphical login manager (runlevel 5) then you will have to choose an alternate method, since CTRL ALT BACKSPACE will only restart the X server in init 5.
So, I usually suggest:
CTRL ALT F2
Login as root, and type:
You can also, while in CTRL ALT F2:
Find all pid's associated with X and kill them.
Another method is to edit your /etc/inittab file, change the default runlevel to 3, and shutdown and reboot. This will start you at a command prompt login screen.
Any of the above should work...
As for the drivers...
First off, you will want to make sure you have the development packages installed, that will include gcc, binutils and so on. If you have gcc installed, it's most likely you will have the rest of the packages as well. Then, get the source tarballs (tar.gz) and use them as they are the most dependable. From there it's a search on this site for 1 of the hudreds of threads on this already, or simply following the README files for the driver