If you need to add more muscle mass, try a medium weight session done three times a week composed of exercises like squats, deadlifts, dips, shoulder presses and stuff like that. It's easy enough to do, and yoga/pilates is also a great idea to strengthen your joints and keep you supple. :D
What does your diet look like? If you aren't eating enough of the right stuff you won't put on muscle no matter how hard you try lol
Peeps, do NOT forget your protein! Most of the stuff I've seen posted up here is about cutting out carbs and replacing it with fruit and veg but you'd do better by increasing the amount of protein you eat too. Aim for at least three fist-sized portions spread out over the day, and include dairy as well as fruit and veg (the more colourful, the better).
I have a great recipe for a fat-free fruit cake which I'll be posting up later, it's gorgeous (and I get to eat some without having to worry about it lol) and my kids love it.
As for weight loss, I'm on the same wagon as some of your guys. I started off a couple years ago as 16 stone 12 and 39.4% body fat and I'm currently 12 and a half at 20% body fat. It's getting there, slow but sure. I do need a kick up the ass though, studying for my degree is taking most of my time that I get away from the kids (ARGH!). ^_^