I recommend installing the newest nvidia-325 from xorg-edgers ppa. To do this, add these two PPA's:
sudo add-apt-repository ppa:xorg-edgers/ppa
sudo add-apt-repository ppa:bumblebee/stable
sudo apt-get update
remove old nvidia drivers
sudo apt-get purge nvidia-304 nvidia-settings-304
Then install bumblebee and nvidia-325
sudo apt-get install bumblebee bumblebee-nvidia primus nvidia-325 nvidia-settings-325
If you are using 64bit OS, you have to install an additional package primus-libs-ia32:i386
Then install Bumblebee configurator, using steps on this site:
http://www.webupd8.org/2013/04/set-up-bumblebee-with-bumblebee.html
In this configurator, set Driver to nVidia and than in nVidia tab change Library Path and Xorg Module Path. Just replace nvidia-xxx (I'm not sure what will appear there) to nvidia-325. Then restart bumblebeed (you can do it through this configurator)
And at last, remove xorg-edgers ppa, because this ppa could mess with your system:
sudo add-apt-reposotory --remove ppa:xorg-edgers:ppa
optirun
for another six months and see what 13.10 delivers.