The left hand side navigation bar definitely have to improve. The width is too big, and the way you place all the links is a mess. Quite confusing, I didnt even know which is which. The center content area have to increase in width, give it more space. The top banner design have to change also, it looks like a rush work to me. And you should edit your page overall width, so that users do not have to scroll between left and right. As for the color scheme, you have relook into it. Try harder...