I am 5'1'' and USED to weight between 120-125 lbs. but during the winter I gained about 10 lbs. and it all went to my butt. I just don't know how to get rid of it. Advice please!

a good diet consisting of complete protein sources, complex carbs and healthy fats. eating consistently during the day, not skipping meals. here's a list of good foods

http://www.bodybuilding.com/fun/stella9.htm

combine that with cardio to stimulate the metabolism and weight training to build lean muscle. you want to lose bodyfat, not just bodyweight