Don't worry. it will do 1440x900 fine.
Try rivatuner or powerstrip or the default way as below:
Right click desktop > properties > settings > Click advanced > click the tab with the name of your graphic card (you should be using drivers from NVIDIA and not the default windows ones to get this tab, i am assuming you are using windows) > click refresh rate overrides > make your own custom resolution say 1440x900 60 Hz.
Apply the settings. check the resolution availability in your desktop settings. Steadily try different refresh rate first in blocks of 5, then 1 to get the maximum bang out of your card. For this to work, your monitor should support the resolution. Else, it will throw a sync error/ blank screen. Note down the last resolution. If Esc button does not get you out of the error screen, reboot in vga mode, after pressing F8 for safe mode options and set the highest refresh rate which did not show any error.
Since you graphic card can do 85 hz even at 2048x1536, you can safely use it at any resolution below the corresponding digits eg anything<2048 x anything<1536 @ 85 Hz. Phew. Thats enough.
Note. this should work to the best of my knowledge. Don't blame me if it doesn't
To err on the safe side, ask some nearby computerwallah to install the lcd at your home. Try this in his presence. If it works, problem solved, else ask him to take the lcd back. Make sure you check for dead pixels on the lcd too. They dont come under warranty.
best of luck for your purchase.
