SAHM with no gym membership

Hello everyone!

Little bit about me:

I am 24 years old, and I had my first (and only) child in November 2010. Before pregnancy I was 140lbs which was my heaviest because before that I was never above 115lbs. I only gained 25lbs during pregnancy (never wore maternity clothes!), and the day I left the hospital I was 145lbs. I was thrilled to be in my pre-pregnancy clothes 3 days after giving birth. I don't have a job so I've been home and without realizing it, I gained 35lbs, bringing my weight to 180lbs. I just finally gave away all my "pre-pregnancy" clothes and for my birthday I bought some plus size shirts and 1 pair of size 14 jeans. Even at 140lbs I was still a size 5 pants and a xs/s shirt, so this has been a shock to me. I've tried counting calories which gets me in trouble because I under eat when I count calories.

My latest motivation? My cousin is getting married at the end of June and my sons godparents are getting married at the end of July. I want to be comfortable wearing sleeveless dresses/tops! I've never been super comfortable showing off my legs because of slight deformation of my knees (from juvenile rheumatoid arthritis my whole life, swelling has moved my knee caps slighlty), but I want to be able to show them off if I wanted to. My wedding dress was off the rack, no alterations...I want to be able to do that again.

Mostly, I want to be sexy for my husband (which he says I am but I don't feel it) and to be able to run around with my son without looking for a bench or chair. I want to be healthy. I want to be able to borrow my moms clothes again instead of having her steal my clothes because she knows I won't fit in them anymore.

It's really hard though. Its wintertime, so walking the park with my son or jogging is out of the question. I have dumbbells and netflix so I try to work out to the fitness videos on there. I am also a member of sparkpeople.com

I need help! It's hard to be superficial with 70lbs of fat on your body!! (<--I'm not really superficial!!)