As you are using images of rectangular style, I will advise you to use a 336x280 size of ad unit. I guess it would fit into the sidebar. Else use a 300x250 unit or else, 160x600 as your current unit appears 120x600.
well... sorry to be sharp but... you need to buy your own domain. then I would get rid of that green color, i think its really bad. next when it comes to adsense, this guy is right. use squares, they seem to perform way better.