Just a question about bed time. How old are your kids? Why do they go to bed so late? Maybe by putting them down earlier that will give you a little more "me" time. (just a thought).
Right now you can start with the basics: portion control, healthful eating habits, smart snacking, etc. Decrease your caloric intake and see how that will affect you. While doing that, make sure you are upping your fiber intake as well as your water consumption. Switch from white starches to whole grains and whole wheats.
AVOID THE JUNK FOOD AISLES AT ALL COSTS!!!
If you have it in the house, you will eat it...so DON'T BUY IT!
Pack a lunch for work every day. ....try to avoid going out for lunch and dinner. Monitor closely what you intake.....and again, make smart decisions.'
Maybe once you have that under control you can maybe try walking on your lunch break. Start wih a half mile walk, then a mile, then a mile and a half and then two. You could maybe even make this a team effort and get some colleagues in on it with you! DON'T FORGET TO PACK YOUR SNEAKERS !!!