NEED HELP WITH THE UPDATE PATCH!!

[sman15rulz]

hey i just installed the patch to update my version to 1.0.0.4 and its great and all but mine goes to 1280 x 1024 as the max resolution. I want it at that because it looks better but its too choppy and laggy. could some1 please tell me how to fix this so i can play with the resolution but with better gameplay. THANKS A LOT!!...