Here are the specifics on how to install the nvidia driver from the Ubuntu repositories, which is the recommended method to install the proprietary nvidia driver in Ubuntu:
https://help.ubuntu.com/community/Bi...erHowto/Nvidia
Since you habe a newer nvidia card be sure to install the nvidia-current driver.
Also install mesa-utils and nvidia-settings.
You may need to reboot to insure that the driver is enabled. If it is not enabled just run:
and that will enable the driver.
Then just run
nvidia-settings from the terminal and it should show you that the nvidia driver is enabled.