Moniter and resolutions on gfx cards

hi i was thinking about buying a 20" lcd screen. it is the one show here
http://www.canadacomputers.com/index.php?do=ShowProduct&cmd=pd&pid=010073&cid=MT.258
its specs seem nice 8 ms is a fast enough response for gaming so i was thinking the resoultion says
1680x1050
my moniter is currently at 1024x768
and my gfx card says it will go up to
1280x1024
i have the radeon 9600xt pro 256mb
is there a way i can get this resoultion higher or will it go higher once i plug in a new moniter?

okay so i was looking in my radeon settings and it said it will go up to 1360x768. is there anyway also to get it higher or whats the deal here

okay now i found a thing called force
and it will force a certain resoultion is thats what i need to do ? becuase it will force the res to 1920x1080 if needed