You shouldnt think in terms of weight, it is deceptive. Muscle weighs far more than fat does. Focus more on body fat percentage. For women, 20%-33% is considered normal/healthy. For men it is about 10%-24%, give or take a bit for both sexes. To lose weight you need to burn more calories than you eat. Sugar is your enemy, simple carbs like white bread and potatos are also bad. Try and eat foods that are low on the Glycemic Index: 12 grain breads, wild rice, unproccessed foods . Avoid spikes in blood sugar(soda pop, skittles, chocolate bars, etc); Fat forms when you have to much energy in your system, when carbs and fat absorb too quickly. 5 small meals a day is good advice.
Saturated fats are to be avoided, but a small amount is necessary. Mono and Polyunsaturated fats are actually good for you, but too much of anything is bad. Lean steaks and chicken are good, I would avoid pork products.
The bottom line is that losing weight is labor intensive, youre gonna have to be dedicated. Spend time preparing good, complete meals. Think ahead, be conscious of what you eat. Multvitamins with all the micro nutrients are a must. Also, it is wise to get your heart rate above 160 for at least 20 minutes a day; that means running around the block 5 times a day. It sucks now, but these habits will serve you well for the rest of your life. You just gotta put your mind to it.
http://www.glycemicindex.com/