Have a look at the slimming world / weight watchers website to see how many classes are near where you live. Unless you live in absolutely the middle of nowhere, you'll have a choice of several classes a week. I live in semi-rural West Yorkshire, and there's 12 classes (7SW, 5WW) within 5 miles of where I live. Although there aren't any on a weekend, there are some on a morning, so it's not necessarily evenings.
You don't have to do the paid-for classes though, there's a great website called www.foodfocus.co.uk where you log all (and I mean ALL - no sneaky snacks!) your food and exercise every day, and based on your weight loss target (I'm aiming to lose 1lb a week) it will give you a calorie target. I've found it great though because it's made me aware of how many calories are in my favourite KFC meal (880) as opposed to a Wetherspoons large cooked breakfast (1550) for example. If anything, it's made me realise that I can eat chocolate and crisps, as long as it's in moderation, and as long as I make up for it somewhere else. Mainly by having smaller portions.
Smaller portions seem like much harder work at first - you just don't feel full afterwards etc, but after a week of cutting your portions by 2/3 or just cutting the protein/carbs/fat by 2/3 and making the rest up with veg you really get used to it.
It's the same with snacking - the more you snack, the more you want to snack, because it sends your blood sugar on a rollercoaster. After a couple of weeks of eating low GI foods (ones that release their nutrition slower, e.g. wholemeal bread compared to a baguette) I hardly snack at all, except for some fruit/yoghurt in the evening when I'm watching TV. And like I said, often with the calorie counting I have enough "free" calories left over at the end of the day so I can have a bar of chocolate or a small bowl of ice cream if I want. Obviously I know this will slow down my weight loss, but if overall it will make it more sustainable (and the dieting more bearable) then I'm happy to do that as long as I'm not putting weight on!
www.minimins.com/ This is a really good weight loss support forum - you'll find loads of good advice and product reviews and a really good support structure.
The main thing is to try and stay motivated - even if you do put on a couple of pounds one week. It's a marathon, not a sprint and it's so much easier to stick with it if you've got something to aim for. Set yourself small, realistic goals (e.g. lose half a stone by the end of the month). Set yourself tangible goals (I have a pair of really nice size 14 jeans waiting in my wardrobe!). If you can, try and find a weight loss buddy - someone who's looking to lose weight as well, and you can keep eachother going when you have a tough day.
This may seem a little extreme as well, but how about signing up for Race for Life? It may sound a little extreme if you're just starting out, but you are allowed to walk it, and with 5 months to prepare, you shouldn't have too much trouble at all.
Also, have you tried going to your GP about your weight? THey can prescribe you Orlistat which prevents your body absorbing fat. THe down side of this, is that it comes out in your poo which I've heard can be a bit nasty, but it's avoidable by having a low fat diet in the first place. They can also prescribe Reductil which is an appetite suppresant, and might help you stay in control if snacking is your bug bear.
Sorry if I've just done a brain dump, but I'm another one that's had a weight loss epiphany! I've lost almost a stone in a month from watching what I eat, but still enjoying a takeaway once a week and chocolate now and again.
Losing weight is hard work, but it is very possible, you just need a lot of will power and self restraint, a fair amount of motivation, and you need to learn that feeling hungry isn't a bad thing! I now relish feeling hungry, because I KNOW my body is burning fat from my tummy and bum.
Best of luck, and I really hope you're able to stick with it