Jgiron is correct. If Crysis is your goal, save up for a new PC altogether.
But if that simply isn't an option, I recommend:
Sapphire HD 5770 - $169.99http://www.newegg.com/Product/Product.aspx?Item=N82E16814102858&cm_re=hd_5770-_-14-102-858-_-Product
This is $10 above your budget but it will run Crysis well at your resolution and you get DX11 for future games (if you move up to Windows 7) and it's easy on your PSU.