First, Watch what kinds of foods you are feeding her. Certain foods make gas, like cauliflower, broccoli, beans, etc.
Second, when my daughter was really gassy I tried Little Remedies gas relief drops and they seemed to help her.
I would also check to make sure that she is using the bathroom regularly. If her bowels are irregular this can really create an upset stomach. Higher fiber foods will help to make her more regular. Blueberries, peas, pears, green beans, apricots, prunes or plums are all really high in fiber and can help. Watch to limit applesauce, bananas, and carbs (low fiber breads and pastas - white and semolina) and try to give her higher fiber items like whole wheat pasta and breads.
Good Luck!!!