Hi Faye!
First of all, congratulations on your loss and fortitude. Have you asked a trainer or assistant at your gym for help? Also, you weren't specific as to what kind of machines your gym has because they vary so widely from gym to gym. For example, I belong to a ladies only gym that offers weight resistence machines. These are not the same kind of machines you'll find at a Gold's gym.
I personally began using free weights after losing 40# and 25 inches. I lost the first 40 by using the machines at my gym and walking on a track. I now treadmill, row and bike or step at home, and lift weights. I started lifting free weights at home 9/15/03 and after 90 days and another 20#loss, I lost 15.25 inches, IMO, a better result than what I previosuly accomplished. I am now in a size 15, compared to 20 years ago at the same weight when I did no exercise and wore a size 20. Although, my belly and butt were the last to catch up with the effects of body building, they finally have. I won't make a decision about the skin until I reach the place that I feel is "goal," but I think the muscle helps fill out some of the sag. Needless to say, I am a free weights body building advocate, and regret not doing it from the beginning. It's also something you can do at home with a minimal dollar investment. By the way, I'm 51. Here are my before body building photos, and the latest when I reached 188#.
http://groups.msn.com/3FCLadiesWhoLift/projectdip.msnw
Good luck, and don't be shy about asking for assistance at your gym - that's what you're paying for.
dip