I'm not sure what sort of workouts you are doing, but i would highly recommend weight training along with your cardio. Women are often scared of doing weights cause they fear bulking up, but that is just a myth. The more lean muscle mass you have in your body the higher your metabolism will be. Muscle takes up a lot less room than fat so you will appear smaller and more defined. I recently started doing quite heavy weights and was surprised that I became smaller in measurements.
I have heard it said that cellulite is unsupported fat - that's why it sags and looks dimply. I would swear by building up the muscle underneath that layer of fat so that it is supported by the muscle.
Obviously the other thing to do is to get rid of the fat and that can only be done by eating right and doing some high intensity cardio. If you have been doing the same fitness routine for a long time perhaps it is time to change things up. The higher the intensity of your workout the more calories you will burn. You are better off doing shorter, more intense workouts than long and low intensity.
If you go to a gym you could ask one of the personal trainers there to work out a program for you. Otherwise, if you prefer to work out at home, like me, you could buy yourself some workout dvds that will help you get into shape and change things up a bit. If you want to start some weight training then i highly recommend DVDs by Jari Love, Cathe Friedrich, Jackie Warner and Jillian Michaels.
