N.C.
It's always best to get calcium from food, but perhaps once in a while you could try the calcium chews, I'm not sure the minimum age.
I teach a nutrition course for a couple different schools. Looking at the list in the textbook, some sources of calcium are:
whole wheat bread (1 oz slice), tortillas (10"). broccoli (1/2 cup cooked), carrots (1/2 CUP SHREDDED), potatoes (1 med, baked with skin), oranges (1 med, raw), strawberries (1/2 c fresh), watermelon (1 slice), tomato juice (3/4 cup), pinto beans (1/2 cup cooked), Peanut butter (2 tbs), sunflower seeds (1 oz dry), 1 hard cooked egg, sardines - better than milk (3 oz canned ), bok choy (1/2 cuo cooked), almonds (1 oz). All but the last 3 are less than 100 milligrams per serving, but making sure she eats a lot of these foods will help. Sardines is about 425 mg/serving and bok choy (Chinese cabbage) and almonds are ~ 80-90 mg/serving.
Does she definitely have an allergy to milk or is she lactose intolerant? They are different things and it is important to know the distinction. If she is allergic, it means her immune system is reacting and she should never have any milk product because it will illicite an immune response. However, if she is lactose intolerant, there are certain milk products she could probably tolerate in small doses, specifically, aged/hard cheese, yogurt because the way these products are processed greatly reduces the amount of lactose. There is also lactose-free milk.