Have you ever considered hiring a trainer for a little bit? You don't need to spend a ton or do it for long, but maybe long enough to have them teach you some moves and design some workout plans for you.
A health blog I read (
http://www.tinareale.com/) is starting an online boot camp program in a few weeks. She will give workouts every week and they can all be adapted to do at home. It only costs $25. Could be a good place to start. Check out this post for a great at home workout
http://www.tinareale.com/1823/move-it-monday-burpee-blaster/
I also really like the Jillian Michaels dvds. No more trouble zones is a great at home weight training workout.
You could also try something like P90x or turbofire.
Good luck!