I am so happy I was able to be of help to someone!
I too was a busy single mom (I raised 4 kids on my own), and had a hugely time consuming executive job. I have almost always used my planning and budgeting methods, although I have perfected them over time; also, I've adjusted the types of meals as the kids grew from toddlers to big kids to teens, the ease of preparation (mostly crockpot dishes during the busy times), and quality of ingredients as my budget grew.
One thing I would strongly suggest if you have teens is to make them a part of it, teach them budgeting and planning now, they will thank you later.
The way we do it in our house now is each teen picks a day (and thus a catagory ie: chicken, pasta etc . . .) and they plan, shop, and prepare that meal for 13 weeks. (after 13 weeks they switch to a differernt day/catagory) They have to go off of my planned menu, read the recipe, check the cupboards for what we have, make their shopping list, go get all the ingredients while I am doing my weekly shopping, and prepare the meal. I supervise heavily, and disasters still happen, but they are learning and it's a good family time (I've found that even the teens who are not cooking that day still wind up in the kitchen - not on the computer- watching, laughing, and giving rediculous advise) . And the kid that cooks doesn't have to help with dishes that night.