Hmm, your situation is tough indeed... But don't despair. First of all, realize that you won't lose weight fast, so prepare for at least 4-5 months of hard labor.
1) Read this simple article about why you're (probably) this fat and on the main idea behind the dieting:
2) Change your eating habits drastically:
a) Go to your local Wall Mart or Target and buy Forman's grill
b) Throw out all junk food out of your fridge. When you shop for food, shop smart - go for veggies and fruits, read nutrition labels - you want to get stuff with as low calorie content as possible, rather than low fat.
c) Reduce your daily calories intake to about 1000.
3) Go to gym. Now, even though I'm not a professional, I managed to go from 225lbs down to 190lbs in about two months, and am approaching my weight goal of 175-180lbs. I'm 5'10" btw. What I've been doing in the gym for all this time is pedaling on those machine that look like treadmills but have pedals instead of the rubber strip. Normally, I would burn about a thousand of calories a day. When I was 200lbs, I switched to treadmills, as they are more efficient imo.
Well, above is what I've done to shed off 35lbs. I feel much better now, I wear clothes that's two sizes smaller, and I can't wait to get back to gym to start doing weightlifting (currently I'm a student, and am a little busy with my classes).
I know that my advice is very amateurish, but it should give you an idea of what you should do. Hope someone will comment on what I said and clarify things. Good luck with your dieting!