Adjust Website Design For Higher Res. Browsers

I currently have a website that already has a design, but the design was created to fit 800x600 browsers. After monitoring my visitor stats, only 3% of visitors use an 800x600 resolution, and I would like to get a design that is more fluid with various screen resolutions. The majority of visitors use either a 1024x768 or 1280x800 browser. I would like the design to be similar to the current design but provides a feel of more room available. I would like to add more features, but the current design limits space, especially in the body of the page. For example, if I add a flash .swf that is slightly too large for the current area alloted for the body, the rest of the design gets messed up, so I have to work around the issue by opening the .swf in a separate window if it exceeds a certain size - the size restriction is a little small. I mainly want to make use of more space than the current design allows, while keeping the site easily viewable from different browsers and monitors. A complete redesign is not necessary, but general improvements on the current design are welcomed. The current design uses a template file and a stylesheet. You can view the current design at www.learn-korean-now.com.