If you have the restricted drivers installed (accessible via system-administration-hardware drivers) then you can run dual screen.
I may be of better help later because I am at work now so I won't be able to give you step by step instructions... just base ideas that I have off the top of my head... however I am running dual screen in Ubuntu on that exact graphics card.
When you install the restricted drivers, it'll also install the Nvidia Settings Manager. The Nvidia Settings Manager is accessible under system-administration... BUT, there's a catch. In order to set up dual screen, you must run the nvidia-settings manager in root... The reasoning is to set up dual screen, it must save changes to the xorg file. The xorg file is the almighty configuration file that keeps the settings for your video output on your monitor.
Open terminal. I believe the command is "sudo nvidia-settings" and it should open up. It may also be nvidia-settings manager or nvidia-settings-manager, but I believe it's nvidia-settings...
On the left side, you'll see twinview. Set up twinview on both monitors. Set your appropriate resolutions that each monitor uses natively and make sure you have the right one selected to be your primary. I personally am running a 19" (1440x900) and 24" (1920x1080) with the 24 being my main.
Good luck.