Hi,
I don't know why you have this problem. I use nvidia GT430 without problems. To install drivers :
sudo apt-add-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get install nvidia-current nvidia-current-modaliases nvidia-settings
But before remove old drivers : sudo apt-get --purge remove nvidia-*
Then reboot and all was ok for me. To set screen size, go to menu>settings>settings manager>display.