How tall are you? Use the BMI as a reference when choosing a healthy weight, but also remember that body type, frame and muscle mass can have a lot to do with the number on the scale. For example, at 5'5 150 pounds people thought I weighed 120 because I was very lean but very muscular. Most people want to see the numbers on the scale fall, but really we're trying to reduce fat and increase body muscle mass. Mass is denser than fat and holds much more water, so when you first start working out you may see yourself gain a few pounds. This is normal. After a couple of weeks the fat you're burning off will exceed the muscle you've gained and you will see numbers start dropping. I would recommend taking measurements as well as weight--measure your thighs, hips, waist and anything else you want to monitor. Seeing those inches go down even when the scale doesn't budge can be very encouraging. Try and find a friend who's active and ask if you can join in on the fun, or get a group together and walk while you hang out together. You don't need access to a gym--just walk more, eat more small meals (do NOT skip meals and do NOT wait until you're starving, this just leads to overeating) during the day, try and add more fruits and veggies in because they are high in water and fiber and low in calories (read: filling without fattening).
Do NOT do any crash diets. Not only do they have next to a zero percent success rate, but they also can harm your metabolism and make weight loss down the line much harder. 30 pounds in three months is on the excessive side. It didn't take you three months to gain the weight, so don't expect it to come off so quickly. Aim for 1-2 pounds of weight loss a week. Eat lots of whole grains, veggies, lean meats, fruit, and low-fat dairy and intermittently enjoy ice cream, cake, candy and chips.
Also check out the website Sparkpeople.com, it's completely free and gives excellent advice on how much to eat, exercise, etc.
Good luck on your road to health!