I am working out daily and need some advice for abd. exercises.?

I have great legs, great but and great breasts but my down fall is my abd. Always lok a little bit pregnant. I am 5'6 and weigh 158 pounds. I go to the gym daily 30 minutes on treadmill, 100 crunches, 50 straight leg raises holding 10 seconds just above the ground (ouch) abd. twist with a medicine ball. I use all the machines I can, leg abduction and abduction, leg curls, back leg curls, back flexon and extension. and any other machine I can use with out using my arms. I have 2 tears in my right rotator cuff and cannot do arm exercises per dr orders. I am on a 1200 calorie a day diet and have only lost 4 pounds in the last 3 weeks. I need to get firmer and better before a wedding in one month. Does anyone have any other ideas out there? I use a program on my Iphone called My fitness pal which helps me to keep track of calories in and used in exercise. Don't let those change the 1200 in. Help! PS I used to weigh 212 and have been stuck in the 150s for a year.