What are good ways to lose belly fat and get a firm butt in 2 weeks?

Impossible. You have to burn off 3500 calories that you don't take in to lose one pound. That's the equivalent of walking 35 miles. If you did that every day, along with eating less, you could lost 15 pounds in the two weeks, but that probably wouldn't be sufficient -- and your feet would be sore. Set a goal to lose weight and keep if off the rest of your life. Start now.
Agree with Dr. Sneid. Spot fat loss does not occur naturally. By losing weight in general a certain amt will be abdominal fat. Eat healthfully ; be physically active. Calories burned must > calories consumed. To tighten ab's do crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge ; “bicycling” exercise on your back. Get regular aerobic exercise. Exercises to tone your butt.