Right the ads are there only in the header (which is a part of the theme), tell me where else do I need to place the ads. This is my blog URL.
I'd put a large square ad above the "Subscribe to updates" on the right-side navigation. These ads perform well, and "above the fold" is good placement.
Think of a web page as a piece of paper. Fold it in half horizontally, and any space "above the fold" is the best ad placement.
Statistically something like 75% of people do not scan down the page below what is first displayed to them e.g. below the fold. So it is vital to have your adsense showing on the first bit of the page they see e.g. above the fold. Hope this clarifies Dickie