Mandy,
The quickest advice I can give you as a certified personal trainer, is focus on cardio, your legs (quads, hams, gluts) are the biggest muscles in your body, when you increase your cardio your muscles will automatically react to the caloric burn. The best exercises are:
Stairmaster - the great thing about this machine is that you can move at a slower pace and receive the same effect as working out like a maniac. You can use a setting of >5 for great results in small increments like 10 minutes at a time.
Spin Class - the opposite end of the spectrum from the stairmaster, but you will yield FANTASTIC results! You can burn up to about 800 calories during an hour long class!
Interval Run/walking on a treadmill - warm up for 5 minutes, sprint for one minute, incline walk for 2 or 3 minutes (or as long as you can without holding on to the bar), then repeat, do this for 30 minutes a few times a week and you will see amazing results.
:Banane43:Jump roping is great too, but it takes a lot of endurance, work your way up to jump roping for at least 2 to 3 minutes a time with a 30 sec break in between (with active rest like crunches, walking in place or anything that will keep your heart rate elevated).
Your body is an amazing machine and what has happened is that it has adapted to the elliptical, change up your routine to create muscle confusion and you will get the results you desire!
Good Luck!