Before you get started, please note that the drivers are beta, I have not tested them (and don't plan on testing the new drivers for a while) and you should only upgrade to the Nvidia graphics drivers 195.xx (currently 195.22) only for testing purposes.
sudo add-apt-repository ppa:thefirstm/karmic-testing
And then install the nvidia-graphics-drivers-195 (including nvidia-195-libvdpau, nvidia-195-modaliases, nvidia-glx-195 and nvidia-195-kernel-source) - you can search for "nvidia 195" in Synaptic to make sure you find all the needed packages.
If you get any dependency errors, try removing older Nvidia graphics drivers.
If you wish to install the Nvidia 185.xx or 190.xx drivers, see HERE.