just picked up a 17inch lcd and want to use it as my slaves screen. just having some problems setting it up.

running both monitors (main is 22inch) off a VGA Y cable (2 into 1). and when i go into nvidia settings i cant seem to find where to set it as a dual display properly. i can get it as a "TV" display, but cant get the resolutions right, and they dont work as dual display like it says. ..