Belly dancing is fun if you have flexible hips and you can rotate correctly. Helps a bit in burning calories and tones a little but if you notice, professional belly dances are notorious for their muffin tops and jiggly bits.
I would suggest 1 day a week of belly dancing to improve flexibility and take up latin, hip hop or body combat if your goal is to lose fat.
As for toning the muscles, keep to crunches and weight bearing exercises 3 times a week for 15 reps of 3 sets. You may not want six packs at this stage but there's nothing sexier than a seductive line that runs through your midsetion.