I need a weightloss exercise program, any advice?

I am female
28 years old
5′ 6
196 lbs

I used to be very in shape and play a lot of sports but excuses aside (I did have some medical problems for years) I want to get back into shape.

My goals weight is: 140 lbs.

I eat good meal choices but my snacks are the killers, I need an exercise program that will help me tone and trim down. I have a treadmill at home, it only has a level 2 incline on it and I enjoy power walking on it. I also have an exercise ball, a small bally ball for crunches and a total gym as well as 2 lbs free weights.

Does anyone know of a good program that I can stick to that will allow me to get to my goal weight in a year. I think I could lose 50 lbs in a year if I really work at it. Does that sound feasible?

Also, what should my caloric intake be if I want to lose an average of 1 to 2 lbs a week? and how much should I be working out during the week?