If your nvidia card only gives you low resolution and/or low vertical refresh, this may be the trick(s) you need.
To find out what values you should have in the Section "Monitor" you can use
in a terminal. Click Cancel in the box that pops up and you've got your monitors horizontal and vertical frequencies. These should be in the section "Monitor"
If you still don't get the right resolution try the following:
Add to the "Device" section of your xorg.conf:
Option "ModeValidation" "NoDFPNativeResolutionCheck"
Apparently, even though the EDID correctly reports the resolution, the driver seems to be getting the wrong Native resolution, so it doesn't think the monitor can handle the actual resolution. The second line tells it to not check for the native resolution. Not entirely sure what the first line does to help, but it doesn't seem to hurt.
Also, if you don't get an option for a higher refresh rate your monitor supports (such as 75Hz) add:
Option "DynamicTwinView" "False"
Dynamic TwinView messes up the refresh rates it'll allow. Note that with this set to False, though, you can not access/set the items on the "X Server Display Configuration" section of nvidia-settings, through the GUI anyway.