I'm 36yrs, I'm 5'7" and I weigh 160lbs at 11mos postpartum to 4th born child. Where do I begin?

My usual weight is 150lbs at a size 10 but I'm currently 160lbs at a size 12. How do I begin? I don't have time to count calories and I can't afford a full half hour for exercise on a regular basis - with 4 young (the youngest is 11mos!) children, the list of excuses goes on - but I honestly want to get moving and make some dietary changes. I've already begun by cutting out soda, beer, excess confectionary sweets and nighttime snacking. I need suggestions for effective and time-efficient exercises and more suggestions about controlling eating behaviors.