if you want to lose weight, you have to have the right attitude. you have to have confidence in yourself, and cannot think negatively of yourself. you cant think of your training and torture.
well, the good thing about exercise is that you can do a whole lot of things...all you have to really do is, well move. swim, bike, run, etc, as long as it gets your heart up, it's great. now, i dont know what complications the surgery brings, but i would consider consulting a doctor before starting a program.
start slow, but stay determined. dont give up. you dont see results immediately, it takes a while. but once you see those results, you'll be hooked.
do not, i repeat do not use diet pills. if you want to lose weight, keep it off and be healthy, there is absolutely no way around it, the only way to do it is by diet and exercise. both are very critical.
keep an eating log. vegetables and whole wheats are your new best friends. avoid white flour and refined sugar. those two things are huge, huge enemies to a weight loss effort. sure, no diet is perfect, but foods like soda, cakes, candy, all the ones your mother told you to stay away from should be avoided at all costs. eat lots of fiber and drink lots of water. use common sense, eat foods you know are healthy.
as i said, i dont know what conditions are with your surgery, so you may want to consult your doctor, and he can better answer how often your body can take a workout.
i really hope this is not a lot to take in. please do not be intimidated by it. i wish you all the best in your efforts. train smart, and most of all believe in yourself.