@Majik. Many of us in this thread have been in that same place you've been. You've already taken the first step of committing to making a change, and posting here (especially with the pictures) is a great first step. Also quitting your job will really help you as it will free up so much time that losing weight should be a lot easier.
First up, before looking into any exercise routines, look at your diet. Starting right now, get a notepad out and record everything you eat for the next week. I'm pretty sure that when you look at it you'll feel pretty ashamed at what you are eating, especially when you work out the calorific content of what you are eating. This is what I did, and just looking at that information really made me think long and hard about my lifestyle. You'll figure out how to change your diet so that its more manageable without killing yourself over the next few months, but this is the most important first step, IMO.
In terms of exercise, right now you should start taking on high-impact cardio activities such as running and swimming. Both of these will be *really* hard for you right now, but both will turbo-charge your metabolism. Right now, you feel tired and sedentary because of your lifestyle. Sitting down all day makes your body change and it gets used to burning very few calories because you are basically doing nothing all day. After a few weeks of running / swimming, you'll actually start losing weight even when doing nothing as your metabolic rate will start increasing.
Most people hate running, and I can totally understand that. I used to hate it too! But I brought myself an iPod and that really helped. Now I really like running as I can put on my tunes and get an adrenalin rush as I zone out and run to my music. I actually find it really therapeutic and enjoyable as a result. However, if you really cannot bear to run, start cycling. That's also a pretty good form of exercise that also has the advantage of being fun. I always like riding up high hills / mountains simply because going downhill on the other side makes me feel like a big kid again!
I'm sure everyone else in here will offer you plenty of advice, so keep chiming in. One piece of advice I an give you is to tell the people closest to you about your plans to lose weight. Keeping motivated can be the biggest brick wall when it comes to losing weight, so having others keep on pushing you and complimenting you when you do well will really help. As I started losing weight, I often found that when someone said something nice to me, it would just make me even more motivated the next day at the gym. So it's important to be able to get that effect from someone / somewhere.
Anyway, best of luck, I'm sure you'll pull it off!