No I didnt read all the posts thoroughly as I dont have time right now, but here is my 2 cents.
WRONG, Do not drink a gallon of milk a day. STOP! Rippetoes book (which I have read, and whose program I am currently doing and refining as I go) does not recommend GOMAD for people who have determined that they need to lose weight first.
You are looking to lose weight. GOMAD is for people who are looking to gain weight. Ectomorphs who need the protein/fat/carbs are recommended to have a full gallon of milk a day with four good sized meals.
Find a healthy weight that is realistic for you (your goal). Go to mypyramid.gov and put your goal weight into the calculator there. Make sure that you don not include that you exercise. This will tell you the maintenance weight of a person at your goal weight who is sedentary, and how many servings of each group they need a day. Build a diet around those numbers that is based on healthy high quality foods that fits in the recommended number of calories. You will lose weight. (This will also be your diet when you get to your goal, so you wont even have to switch anything. Just stay the course.) Dont eat after 7 PM.
After a week of healthy eating, weigh in. If you have not lost weight, decrease calories by 500 calories and go another week before changing anything.
Weigh yourself in the morning, before you eat or drink, in your boxers, and after you use the bathroom.
Stay away from bodyfat calculations and that garbage. Just use a mirror, a scale, and your logbook to asses your progress or lack thereof, lest you start to major in the minors so to speak.
You dont have to be a diet nazi either. That is not what I am saying. You are allowed to "cheat" because if you dont, you will eventually burn out and quit your diet. So just be firm, but relaxed at the same time.
I would recommend that you continue lifting weights (safely and doing the program you have decided to do correctly as it was intended and written, and not how you heard that your friend's friend's cousin's step brother did), and that you add some cardio (whatever you enjoy that you will actually do).
This should all be manageble stuff.
Also if you need pointers on doing starting strength check out my log (Zep's las stand) and post your question there. Also, there is a guy on here called TheDudeAbides. From what I gather, he seems to have started in a similiar place with similar goals, and now he is strong as hell and leaner (check out the log called The Dude's Rip Log). He would be the man to ask for advice in my estimation as he has already done something similar to what it sounds like you want to do. If you want to be where someone is, then do what they did.
Do not expect over night results. They dont exist. Sorry.
To everyone else, I didnt recommend any kind of crazy bodybuilder diet or crazy shit because it sounds like the man is looking for a lifestyle change whilst getting stronger (or at least maintaining strength) in the process. I dont think it is wise to start out eating like the hardcore powerlifting crowd does (they dont care about fat loss at all from what I can tell) right away either because he mentioned that he wanted fat loss. I feel like these things fit his goals better.