I think your placement is OK. Try testing a few things, eg the color or the links. Try #0000ff instead of the current shade of blue and see if that brings up the CTR. I also think there's a fine line between placing your ads where visitors can't help but see them, and positioning them so they scream ''AAAADDs!". I like the way it matches your design, but that skyscraper might just be a little OTT! Why not try a 2 column theme and place a large borderless rectangle within your text under the header with regular blue links against white b/g.