I'm thinking that is your max res on the TV.
FTR, VGA can handle resolutions way over this, but not all TVs support high PC resolutions, the good ones do. I know my former roommates TV, a Samsung, used a VGA input for the PC and it supported full 1080p input.
Does the 9800GTX even support sound out of the card? If it does, I was unaware, I know that the ATI cards can do it.