Have you spoken to your doctor about your exercise program? If not, head in and have a chat.
As for the weight gain, that's common, normal, and will even out eventually. www.sparkpeople.com/resource/fitness_artic
I will preface that with the comment that this is dependent on your diet; even if you're exercising, you can still gain weight if you eat too much. You can't out-exercise a bad diet!
Weight loss is about eating less than you burn... not the exercises you do.