If you are lookin to see how much you will make with your current card you can look it up here:

https://en.bitcoin.it/wiki/Mining_hardware_comparison

Find your card and put you hash rate into:

http://www.alloscomp.com/bitcoin/calculator.php

You can look up exactly what card you have with:

http://www.ozone3d.net/gpu_caps_viewer/


 I myself get a very low hash rate.  Equals out to be 14$/month with the current exchange rate.  I ended up hooking up all my computers in the house to mine.  I'll end up with about 45$ a month which isn't really to bad will be enough to get another video card soon.  I already have plans to build a new rig.  -_- damn you bitcoin you are addicting.  There is a nice hardware guide out there if your interested I can post up a link.