I'm by no means an expert but I think you may want to check out the aerobics classes. They may not be as intense but they use different muscle groups than the elliptical and running do. If your body uses the same muscles all the time then it gets used to it and you don't burn as much. If you add new things, like aerobics then new muscles groups will be used. If you think it will burn you out then I wouldn't do both. I usually do both an exercise tape in the morning (when I want a little extra exercise) and my normal bike/treadmill routine at night. It's up to you. Anyway, just my opinion.
December 2005-lowest weight of 148.5
Start weight Ocotber 2010-186.6
Current weight 178.5
GW-140 April 2011