Ooh, now, I'm straining to remember how this works. But I'll be nice and log into a Win2k machine here and look it up, if, erm, system permissions allow me to see that!
Try this:
Go back to that display settings where the resolution slider is. Click on Advanced at the bottom. Then click on the Monitor tab in the new window. Then the Properties button. Then the Driver tab in the new window. Then click on Update Driver. Then in the Wizard, Next on the first screen, Display a List... on the second screen, then click the Have Disk button and navigate to the .inf file.
I think this is how it works (and incidentally I know love my Mac even more than I did before I explained this to you!

). Good luck!