I would put some more "in content" ads on your main page, since I only see one add currently being displayed. Since you already have a lot of small pics to go with your content, you could easily throw an ad or two in beside a few images. Just make sure you have some sort of border separating the images from the ads. You might also want to add in a box-style link unit to the right of (next to) your navigation links. Hope that helps some!
Maybe it's just my computer but you have an ad positioned on top of a link to one of your articles. If that was done on purpose, I would suggest you find another location for it.