Ali,
I know that it is difficult to make time, my kids are now 14 and 12 and it is still hard. I found a great exercise DVD. It is the Biggesst Loser 2. What I love about it, is in the menu you can choose the timed routine workouts and put them together, so if you only have 15 minutes, that is all that you do and you will feel like you completed at workout. If you have more time, than add in a few extra workouts. there are 9 different workouts to choose from and warm up and cool down. I love this DVD plus, these people inspire me. Check it out! Good luck!