ask your coach or other skaters at the rink. your coach may help you with that by showing you some off ice exercises that may help with your skating. my friend's coach held classes at her house every alternate week to strengthen their muscles.
if you can, go for runs as well. you need stamina to keep up with practices adn make full use of them.
you cant go wrong with doing some simple gymnastics exercises. it'll be good to take up some dance classes, so you'll be more aware of your body posture.
before you eat enything, ask yourself, am i hungry? is this a whim or do i really need it? less soda, more water!
sometimes subtle things cut back your weight too. but of course, all these take time to show results. persevere!
stay happy, laugh more! that has got to the be truest medicine.