You have to first add the xorg-edger repository to your sources list, then update the sources, upgrade the packages and then install. The package is not called "nvidia-current", but nvidia-graphics-drivers-331
All this is easy if you have synpatic
sudo add-apt-repository ppa:xorg-edgers/ppa
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install nvidia-graphics-drivers-331 ppa-purge
Then open Settings> Repositories > Other Software
sudo apt-get install synpatic
close the drop down
Then you can search for nvidia in quick search and see what packages are available and you don't have to know their exact names like with the commands.
The smiley is actually a colon, somehow it shows up as a smiley.
1. ppa-purge is installed in case anything goes wrong you can reverse the change.
2.There was a packaging bug in that when you install nvidia-driver from xorg-edgers it somehow install bumblebee and primus, these are for optimus laptops. If you don't have optimus you will boot into a blackscreen because bumblebee blacklists the nvidia driver, assuming that there is an intel card for fallback. I don't know if that has been fixed or not. So after you install, make sure that bumblebee is not installed and if it is remove it before you run nvidia-xconfig and reboot. synaptic is very handy for this
3. If everything works, disable the xorg-edgers ppa so that you don't get frequent updates that may be unstable (easy to do in synaptic, go to Settings > Repositories > Other Software and uncheck the box)