I need to get fit

I am trying my best to get in better shape. Even though it sounds goofy the Wii fit is really helpful especially on those days I can't or don't make it to the Gym. I know that it works because the other night I spent the night at my sisters house (I was watching my 13 year old nice and her friend while my sister worked a night shift.) and I did the Wii fit for 2 hours and for 2 days and I can completely tell it's working. My legs are so sore from doing squats and Yoga. According to the Wii I need to lose 11 lbs to reach optimum BMI. I just want a body that I am not ashamed to be seen in a swim suit in. The problem I have is because of my back I am very limited on what exercises I can do that will not strain my back. Hopefully I will get in to see a Dr. this week. I don't want to have surgery before the summer though because I want to be able to have fun on vacation. I don't know maybe I could heal fast? I have never had a prosthetic disc before but I am happy about the prospect of not having anymore back pain. :D