Performing certain exercises in certain areas of the body to lose fat in those areas is one of the biggest myths floating around... Unfortunately, your body will burn the fat wherever it sees fit, which is determined by your genes. Doing both cardiovascular and strength exercises are crucial to losing fat mass, but there's no specific exercise(s) that will burn fat from the abdominal area.
If your stomach is not flat at that weight, you may need to add fiber to your diet. You must be constipated or be bloated with gas. Yoga can also help these issues.
When you exercise, you must work your muscles and concentrate on holding your abs flat. If you push them out, you are teaching them to protrude.