I would suggest setting a goal that is specific. A lot of people like to start out with 10% as a first goal. For me I started at 227, so 23lbs was my first goal. My second goal was to get under 200. Third goal is to get back to "pre-baby #4" weight (or 185).
Next, you might look up your Basal Metabolic Rate to get an idea of how many calories you need every day. Add 300-500 if you are nursing. This formula works for me anyway.
I know how hard this is with little ones about! Time is precious for sure!! I like to use exercise tapes. If you check them out from the library you can try them first. Also, eBay is great for cheap ones.
Best wishes, and good luck with your goals!