Hey Pete, you cannot make your upper body smaller (spot reduce)to have a more balanced body contour, but you can make your legs bigger (not fatter) and that will balance it out quite a bit.
Try for lunges and those ever so dreaded Squats. Squats are a girls best friend. Also, leg lifts, leg curls, Hamstring Curls, Calf Raises, Leg Press(if you got to the gym). Many things you can do to exercise your legs and make it more even all around.