Ok, I think I have some ideas for you, and I will give you some links to tools that will help you.
You will need to reduce your calorie intake to 1200 calories per day. Make sure not to go below this level, since less would not be nutritionally adequate. Also it is very important to eat the right balance of different foods to get the results you want, so you need to track portions of food groups as well as calories.
Here is a link to a tool that will help you figure out how many servings of what, and what the portion sizes are: Mayo Clinic Healthy Weight pyramid tool Fill out the information and it will give you the pyramid for you, as well as a document you can print out that lists portion sizes of different foods.
And for foods not listed there, here is another link: CalorieKing.com It will list just about anything you can think of, and it is free to use. There is other nutritional information included, not just calories.
Another link that may be helpful, to track your diet: Livestrong's MyPlate
In general, the concept of using your plate as a guide is a good one. Use a 10inch plate and divide it into quarters. 2 quarters (1/2 the plate) should be vegetables and fruits; 1 quarter for meat; and one quarter for carbohydrates (bread, potato, corn, pasta, rice, etc).
For you specifically here are my thoughts:
Breakfast: Add a cup of milk (low fat or nonfat) and a serving of fruit. Also, be aware that the granola bar probably has at least 1, maybe 2 servings of fat, and some extra sugar.
Lunch: Have a bigger salad, 1/2 sandwich (less fat, and less carb). Use fat free Ranch dressing. Use either the salami or the cheese, not both. And check the list for a serving size of peanut butter. And no potato chips (too many calories and fat grams). Choose something else off of your list.
Dinner: Watch your portion size for meat. One serving of beef (per the Mayo diet) is 1.5 ounces because of the fat content; Chicken is 2.5 ounces and fish is 3 ounces.
Obviously having chicken or fish would be more satisfying and would give you less fat grams.
Add another cup of milk (or a yogurt) during the day to ensure you are getting enough calcium. Plus, studies are suggesting that people who get enough dairy in their diet will lose weight more easily than people who don't.
The Mayo diet seems a bit restrictive, but it is effective. Its all about balancing your allowed portions. Adding the extra cup of milk will give you 4 servings of protein/dairy per day, but I think it is worth the few extra calories as long as you use nonfat.
Any cheese you use should be fat free. Cheese is a good source of protein and calcium, but unfortunately is also has too much fat.
As for thyroid issues: If you think you have a thyroid problem, you need to discuss this with your doctor so some tests can be done. Chewing ice can also be "a habit", or because it is something to chew on that has no calories. People who are deficient in protein can also have this fascination with ice chewing.
You also need to increase your physical activity. Ideally 60 minutes of exercise is needed daily, especially since you have a job that keeps you sedentary. You can use part of your lunch break to walk for 30 minutes a day in addition to the exercise you are currently doing. These types of activities are not enough though to really get your body into weight loss mode. You should also add some weight training at least 3 x week. To do weight training properly, the best thing is to join a gym at least long enough to be taught the proper techniques, then you can continue at home.