Your exercise is not enough. I know we hear a lot of talk about how keeping the heart rate up for 20 minutes is good, but that information is directed at older people, not you or I. They're talking about heart health, not weight management or weight loss. There's no surprise that you haven't lost any weight.
The kind of cardio you need, be it treadmill or aerobics is 45 minutes non-stop (at least), 3 - 4 times a week. Shoot for a heart rate of 140ish.
Remember, it's not just how many calories you eat, it's what kind of calories you eat. Stay off the dairy and the grains (use potatoes for carbohydrates). Please don't listen to the people here telling you to cut calories, your number of calories is fine. Go for foods that are high in mono- and polyunsaturated fats (avocados, almonds, olive oil, dark chocolate).