Great job on losing 70 pounds. You must have worked VERY hard.
You can't exactly "tone" a muscle. To get a look that is what most people called "toned" muscle needs to be built up and the fat that is covering the msucle needs to be shed. Are you doing any strength training? Strength training is an important part of any workout program. It burns loads of calories, keeps our muscles and bones strong, and develops a good muscle base, which gives our bodies a firm, fit look. As we age, we all naturally start to lose muscle mass. Less msucle mass equals a lower metabolism.
When you do strength training it's important to work all the muscles, not just your problem areas. If you're not strength training already and would like some help, feel free to let me know. And if I've just given you information that you already know, sorry!
Sarah