What graphics card do you have? Please provide make & model number. It may be showing up as 1440x900 max at the moment, as you have your CRT connected. If that's really the max it'll go, there may be a tweak to get it to the correct resolution, which may include installing the latest drivers for the card.
As far as possible, always run TFT LCD monitors at their 'native' resolution - for most 22" widescreen ones it'll be 1680 x 1050. Otherwise, you could be quite disappointed with the quality of picture, text, etc.
If you cannot get your graphics card to run at the 1680 x 1050 res with the new monitor, you may have to purchase a graphics card that supports that res. G