You should put a 728x90 instead of 468 on the top and align it to center. image and text.

Slot in 1 large rectangular between your post in the index page. Add in a 300x250 on your sidebar bottom or between categories and facebook.

Word of advice, you better get that Adsense block away from the blog post title.

hxxp://smartpet.net/2011/10/22/lars-the-social-butterfly/

Looks like your trying to trick the traffic into clicking by having that blog title right on top of the Adsense block. Add some space & a line between them. Also the blog text below the Adsense needs backed off a bit, If you plan on keeping the Ad block.

I second Yukons suggestions on making it TOS complaint, you need to do that on the homepage as well. I'd try a 336x280 text ad right above the search box in the right hand column.

I would advise you to read these AdSense help articles by Google...
https://www.google.com/support/adsen...ips.html#17954

Hope this help!