Hi, and welcome
You've taken the first, most important step, in my opinion, which is asking for help. So well done for doing that- even that can take some bravery. And I'd dispute that you have zero motivation. You said "I want to live a long life for my daughter". That's a whole heap of motivation right there- or at least some incredible inspiration to give you motivation.
The secret to weight loss is eating less calories than you burn. No, that doesn't mean you need to go crazy and burn 2-3000 calories a day. In order to work out how many calories you need, find a BMR calculator (search "BMR calculator" on a search engine and they'll pop up all over the place) and calculate your maintenance calories (the amount you'd need to eat to stay the same weight that you are). Then reduce from that either 30% (which is a number recommended around here) or between 500 and 1000 calories (with 500 you should in theory lose a pound a week, with 1000 in theory two- as a pound of fat is worth 3500 calories). Never reduce that number below 1200, or 1000 under maintenance, or you risk slowing your metabolism and giving yourself greater health problems in the long run. The number you get (I'd calculate it for you, but I don't have all the necessary information) is the amount of calories you can eat in a day. I look on it as a budget.
There are lots of different diets out there, but the ones that work all have behind them the principle of calories in/ calories out. At a minimum I'd suggest becoming more aware of the nutrition in your food- read the labels, make lower calorie choices where you can. Ideally calorie counting is the way to be most in control of this (measuring/ weighing your food and tracking it on a program like fitday, which is highly recommended around here). At the end of the day, you need a system that works for you. Calorie counting is working very, very well for me, but not everyone likes that sort of system.
In order to find out more about food and nutrition, I'd recommend reading the stickied posts (the ones at the top of each sub-forum), which have some really invaluable information in them. I'd also recommend looking to the health guidelines for your country for an idea of what you should be eating (or alternately, the NHS in England, where I am, has some really easy to understand information: ). Find foods that you enjoy and that are healthy- berries are a good example. Also find foods that you find filling and include more of those in your diet (for example, I swapped cereal for porridge/ oatmeal, as it's much more filling for a lower calorie allowance).
In terms of exercise, take things a day at a time. When I was just about to turn 21 I had glandular fever (mono) and ended up being bedridden for six weeks as a result of some rare complications. I was incredibly weakened as a result of that and became very dependent- I had trouble walking to the other end of my house to go to the bathroom. I started to see a physiotherapist, who recommended baby steps. He got me walking 10 minutes a day on a treadmill, at a speed I was comfortable with (very slowly), and increased that speed by a minute a day. I went, slowly but surely, from spending all my energy walking to the bathroom once a day, to walking briskly and running on the treadmill for an hour a day. I also lost a bucketload of weight (40 kilograms, or 88 pounds- from 100 kilograms of 220 pounds). I recommend a similar approach for you. Walk a little- to the end of your street, a couple of houses down from you, something that's a little bit tiring but not exhausting (by the time you get back, not just when you've gone one way). And every day, walk a little bit further- for an extra minute on top of what you did the day before. You'll find your fitness increases a little every day. Keep the steps up trivial so it's not daunting. Any exercise is better than no exercise, and this is a good way to start.
Finally, for additional motivation, I suggest visiting the diary and before/ after sections to see what other people are doing and have done- you'll see that it is possible, and get some ideas of what you can do yourself.
Good luck, and again, congratulations on making that first step
