Hi there and thanks so much for posting this question. It doesnt surprise that you can't lose weight . In my opnion you need to change your eating habits focusing in speeding up your metabolism. You need to eat small meals three to five times a day. This way you will increase your metabolism.
With a consistent increase in the calorie intake you will speed up your metabolism and is really possible to hit the recommended half pound to two pounds of weight loss per week.
Why is that? In order to burn calories the body needs calories. Actually cutting calories can slow down your metabolism
However I want to make sure that in order to increase metabolism you need to increase the consumption of great nutrients like protein, fiber, vegetables. if you increase sugars and carbohydrate your body will do the reverse and gain weight. Make sure you keep drinking water (6- 8 glasses a day) and add your strength training workouts (3-4 times a week- 20 to 30 minutes) and cardiovascular 3 times a week for 30 minutes.
Check this video how to increase metabolism http://www.youtube.com/watch?v=5WuYB_bJXLw
and for my exercises search "michael gonzalez-waalce" or "super body super brain"
Hope you are well and hope this helps!