Hi Liz,
I have 2 kids-Hailey is 3 and Gabe is 5 months. I am also around your height and weight so I know how it feels. My mother in law just bought me a baby tee that is a XXL and it fit, so sad. I have been trying to do WW at home; I have the supplied via ebay. I have not been doing too well lately, though tomorrow is another day and I did lose a pound this week and started to work out.
I started to use the biggest loser workout dvd with Bob. I like it b/c it has different programs and my body isnt used to exercise like it did pre-children. If you need a diet buddy, lemme know

Good luck!