IE issues

http://www.misplacedgrenade.com

I’ve been having compatibility issues where my site looks fine on browsers such as chrome and firefox, but when view in ie 7-9 it looks terrible. the side bar is pulled down and the buddypress bar in on the bottom instead of the top. what should i do to fix this, also the css shadow doesn’t appear either and i know that is the browsers fault but would like a substitution for that. thanks!