Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
What do you mean, that you "can't find the right resolutions"? Does System Preferences > Displays not show the correct resolution, and if so, what resolution does it show?
And what Mac OS X version do you use?
 
Well, there is no resolution 1920*1200 in my list in System Preferences. I use Mac OS X Lion 1.7.2
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.