The best way is to download nvidia driver from the official site.
Shutdown Xorg by droping to a single user mode:
Backup existing /etc/X11/xorg.conf to /rootCode:init 1
Unpack and install the driver. It will prompt for settings and select appropriate screen size and other stuff. Start X again by switching to level # 3:Code:cp /etc/X11/xorg.conf /root/xorg.conf