The reason you don't see resolution option in nvdia-settings, is because you probably didn't install the nvidia driver. You should install the nvidia driver of your corresponding gpu
with this command :
$ sudo apt-get install nvidia-current
or you can go to follow this link: http://www.nvidia.com/Download/index.aspx?lang=en-us .
After doing this reboot, and type in terminal:
$ lspci -vnn | grep -i VGA -A 12
You should see : "Kernel driver in use: nvidia"
instead of ubuntu default driver "noveau".
After doing this type in terminal:
$ gksudo nvidia-setting
and change settings to desired resolution in " X server Display Configuration"