Looking at the entire amount you'd like to do can be so overwhelming... I'm shooting for a 100lb loss, but even THINKING about it is discouraging. Just take it one day, one choice at a time, and believe in yourself. I KNOW you can do it, and you have a wonderful husband to help you, and a daughter for motivation.
I don't look at it as a "diet" because diets have a beginning and an end. I look at it as a lifestyle change- changing the way we do things, be it activities, celebrations, snacks, and mealtimes, to make a BETTER ME, and help my (future) children be healthy. I want to be healthy for them, just as much as I do for myself.
Just about any plan works. Atkins. Calorie counting. Weight Watchers. South Beach. You can find success with any of them, or you can ditch the formal plans altogether, and just make better choices. No matter which route you go, just pick one that's REALISTIC for YOU, and don't let one poor treat or dessert throw you off all day or all week.
Now I suppose I'm just rambling. Welcome to the forum, and I hope you take this journey WITH us, we're all here to support and encourage.
I KNOW you can do it.