sounds like you are doing exactly what you should in terms of diet and exercise.
I would suggest a few things:-
1. Get your thyroid checked. Low thyroid is a very common comorbidity with diabetes. It an make weight management nearly impossible.
2. Ask your Dr. if you can try metformin (it helps with reduction in insulin resistance and therefore with weight loss).
3. Try very low carb, moderate protein, high fat diet. YOu can read up on this via. Diabetes Solutions, Dr. Richard Bernstein. He also talks about his diet on U-tube at Bernstein Diabetes University, along with heaps and heaps of other useful information.
Hope this helps.