The site looks very good, easy on the eyes, easy to navigate, i really like it.You have a PR of 5, allmsot 1000 pages indexed in Google. I think you are doing just fine.
The theme was already designed, but I modified it heavily so it's hard to tell it was a theme before. I've added many things, such as the side bar menus and to the individual pages. Many things that did not come default.
Its very nice, good color scheme. maybe make the text larger since its a very content heavy site, and it would be easier to read that way. like size="2" or 11-12 pixels.