It sounds like you already have a handle on a lot of good things... Mommy and Me is cute for the baby, but yoga may be more fun for you... you use the baby to help you, and I've heard from some women that its fun and you get to exercise, which is a bigger bonus than someone singing "Itsy Bitsy Spider" to your four-month-old when they have no clue what's going on.

But its a good way to meet other moms.