As Chelonian mentioned, your daily caloric need is 1,650, plus whatever calories you burn during exercise. Also, you can't "spot-reduce" fat. So losing the 12lbs or so of fat in two months doesn't mean it will come from your abdomen, nor does it mean you'll actually get the results you're looking for, depending on what your goal is.
Additionally, if you're doing the crunches in an effort to lose the belly, it's a futile effort. It will help you (sort of) get well-trained muscles, but crunches really only work the surface-level muscles. And again, you can't spot-reduce fat.
At your current weight, running for 20 minutes at 6mph burns about 270 calories. "Cross training" is kind of vague, but let's say it burns 230 calories for 15 minutes (for the sake of math). That would be 500 calories you're burning, on top of Chelonian's calculation of 1,650 calories, for a total requirement of 2,150 calories.
Generally speaking, it's recommended to have a goal weight loss of about a pound a week. That requires cutting back by 500 calories per day. This means that, with your current exercise, you can eat 1,650 calories and lose a pound a week.
However, as I mentioned earlier, you may still not get the results you're looking for. Cardio is great for reducing fat, but frankly, you'll very likely just end up a smaller version of your shape right now, and still feel and look "flabby."
To help remedy this, it's a good idea to include full-body strength training in your workouts. This can be bodyweight stuff, such as push ups, bodyweight squats, and so on, or it can be weighted stuff, such as barbell squats and bench presses or kettlebell work. This will help maintain muscle mass, which will give you a more "firm" look as the fat comes off. And no, you won't turn into She-Hulk if you pick up more than a 5lb dumbbell (in fact, most women are smaller than they were at the same weight), so don't be afraid to go after the Olympic barbells or the 25lb kettlebells if you have the strength to use them with good form. For detailed information, check out New Rules of Lifting for Women or even Starting Strength.
Also, see about trading in your consistent treadmill runs for sprint intervals, especially if you're increasing the duration of your runs. This is known as "High Intensity Interval Training," which has shown to be more efficient at fat burning than steady state cardio (ie - 20 minutes of high intensity intervals burns as many calories as 60 minutes of steady-state). If you're just starting out with running, the Couch to 5k program uses interval training to work you up to 5k (~3 miles) and is a good one to start with.
Finally, for diet - be careful restricting your calories too much. If we assume that your workouts burn 500 calories, and you're already at a deficit of 650 calories (1,650 - 1,000), then you're taking a total deficit of 1,100 calories, or a little over 2lbs per week. This really only works for people who are severely overweight and have 100+lbs to lose. While you have a decent amount you could lose, you're still at a low enough weight that this kind of deficit can backfire on you, in a number of ways (including plateauing). Additionally, eating such a small amount can lead to nutritional deficiencies, and just in general not being able to fuel your body's needs, leaving you tired all the time and requiring longer time to recover from intense workouts. If you find that happening, don't be afraid to increase your caloric intake by a couple of hundred calories.
Make sure you're eating good whole foods. 1,000 calories worth of pizza won't get you far (and really, isn't that much pizza if you're getting it from a pizza joint; Pizza Hut's pan pizzas run about 400+ calories per slice). Good, whole foods, like steak and broccoli will carry you a lot farther.
If you're not already, start tracking your food. I personally use MyFitnessPal, but there are others. If nothing else, use it for a couple of weeks to make sure you are, in fact, only eating the amount you think you're eating (and conversely, that you're eating as much as you think you're eating). A lot of people grossly underestimate how much they're eating, and it's good to get a baseline idea. Additionally, it allows you to see what it is you're actually eating, since a lot of people don't think about it much and think they're eating healthy, only to find that they have 3 servings of cookies and a 20oz bottle of Mountain Dew every day.
If you carry most of your weight in your abdomen, then you might want to look into gluten-free and/or lower carb ways of eating. "Beer bellies" that aren't actually caused by drinking a lot of beer are often caused by insulin resistance and/or gluten sensitivity/intolerance. It might be worth trying each for a month or so to see if it has any effect on your tummy area. Again, it comes back to eating good, nutritious whole foods. Shop around the perimeter of your grocery store, or better yet, go to a farmer's market and butcher shop to get the bulk of your food.
