The other posters are accurate about the loose skin, it's not something exercise can fix because our bodies don't metabolize skin. However, I've been doing a little reading about that problem today and there is a little you can do to help. In the end, surgery is truly the only way to completely get rid of the excess but you might be able to improve the situation to a point where you are satisfied or at least will put you in a place where surgery will have a higher chance of complete success. The first thing I would do is talk to a dermatologist about your options. Here are some links to peruse:
Team Beachbody - Newsletters (scroll down to the loose skin portion)
How to Tighten up Loose Skin After Weight Loss | eHow.com
Plastic Surgery After Weight Loss - Watch WebMD Video
But not all hope is lost! Exercise will help to some degree because your body composition will change, you'll further drop body fat and add on muscle mass. Your weight right now puts you right in the normal range on the BMI scale. Admittedly, BMI doesn't tell the whole story, but at least you're starting from a good place.
Calculate Your BMI - Standard BMI Calculator
Your diet is pretty much exactly what I would recommend although I would encourage you to make it a point to eat dinner, and eat it no sooner than 3 hours before you go to bed. This will help your metabolism while you're sleeping. I also suggest to finish your meal with green tea. You are already doing yourself a big favor by eating breakfast and continuing with small meals and snacks throughout the day. It's no wonder you were able to lose so much by dieting alone.
the equation you want to do is called the Harris-Benedict equation.
Go to this link and fill in the info to get you Basal Metabolic Rate:
BMR Calculator
Then multiply the number you get by one of the following factors based on your current level of activity:
1. If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
2. If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
3. If you are moderatetely active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
4. If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
5. If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9
In your case if you consider yourself moderately active (treadmill 30-60 minutes, 3-5 days a week) then your maintenance level would be about 2180 calories a day. If you eat that many calories a day and do the exercise, your weight will not go up or down significantly. You will certainly lose body fat % over time while increasing your muscle mass though, and that's where the money is.
I don't advocate for strict calorie counting because then it becomes obsessive and gets in the way of you living your life. I prefer to estimate but it takes some practice to get comfortable knowing how many calories are in everything you eat. A good starting place is a website like fatsecret.com or livestrong.com where they have a database of the nutritional info on all of the common foods and many restaurant chains, or grocery store products. You can enter in what you ate and keep a tally that way, or just keep a journal. Again, after a while you'll get a feel for how many calories are in a handful of almonds, or a grilled chicken salad and you won't need the journal as much.
Do you have any health issues that would prohibit any kinds of activities? Knee problems, arthritis, previous sports injury, that type of thing? I ask because there are a number of really great programs that you can do in your home that can help you with the areas you said you'd like to improve. Palates and yoga come to mind right away. There are inexpensive DVDs at BJs for these workouts, or you can go with a more pricey option that is a more complete solution. I use Beachbody products and have seen awesome results. For most people it seems that changing their diet is the hardest part and since you've already done that, adopting one of these might be right up your alley.
If that's not something you want to do, start with the cardio workout I mentioned before and set a goal to run a 5K this spring. I did it last year and not only did I finish (started from being sedentary) but I got a better time than I anticipated. If that workout leaves you wanting more, put on the ankle weights for your jogging. I'm sure you can either find a cheap DVDs at BJs, or some videos on youtube to show you what exercises to do for your upper body and abs.