My advice would be to have your body fat tested. That's a better indicator of health vs. a number on the scale, especially when you're at a healthy weight for your height. The results of that test will help you determine whether or not you have more fat to lose, and if so, how much. Most gyms offer this test for a small fee.
In general, I recommend 30 (or so) minutes of cardio exercise, 3-5 days per week, as well as a full-body strength training program 2-3 times per week.
"You may have a fresh start any moment you choose, for this thing that we call "failure" is not the falling down but the staying down." Mary Pickford
"No matter how slow you go, you are still lapping everybody on the couch."