Welcome! It's so hard to take off that pregnancy weight, isn't it? I used to have a nice flat toned stomach pre-pregnancy, and now I just have a large pouch that pokes out, courtesy of an 11 pound baby. I definitely think lifestyle change is the way to go. If you eat the right foods and stick to fruits, vegetables, and lean protein and avoid red meat and processed foods (as much as possible), you can eat SO MUCH food and still be under 1500 calories and full of energy.
How old are your kids? My daughter will be four at the end of August.