can you post a link so we can all see it? No doubt we will have some suiggestions.
I would however make the following observation,
Your resolution is not one of the standards that is designed for, In my case I design for 1024* 768 which is the most common resoution size. (Screen size is immaterial it's the Pixels you need to worry about) I never design for 640* 480 as thats dead and buried but I do make sure all my sites are viewable at 800* 600 px.
With the coming of bigger screens no doubt designs will have to be modified but I always design for the most used resolution. Distribution is most commonly shipping 19" and 21" monitors which have a native resolution of 1280* 1024. It follows that with all the exisiting monitors 1024* 768 is currently a good resolution to design for.
That being said my PS3 shops look ok at 1280*1024, 1024* 768 on both standard PC monitor and wide screen tv/monitor.
Anyway post a link