Shy-anne,
research all that you can on High Intensity Interval Training..HIIT. It is intense, but highly effective "cardio" training. It burns fat faster than long steady state cardio like jogging, treadmilling, walking..and some build some nice muscle on it.

Also get yourseld familiar with EPOC..excercise post oxygen consumption..

Here is a good article from Muscle Media going over HIIT..they use sprinting as their HIIT movement, but you can use a stationary bike or even a treadmill

http://www.musclemedia.com/training/hiit.asp

Good luck..