N.M.
You sound like my son. :) I've tried different alarm clocks and it doesn't matter how loud and obnoxious they are, he will sleep right through them. Me, on the other hand--I hear it but my problem is hitting the snooze too many times. One of those chase-it-to-turn-it-off clocks might work for me, but not him.
Anyhow, your best bet might be to start now getting up a little earlier each week so you are ready for August. Try this... whatever time you get up now, set your alarm for 15-20 minutes earlier than that for the next week. Like, if you usually get up at 10, next week get up every day at 9:40. It shouldn't be so much earlier that you can do it, and maybe your body is already starting to wake up and will hear the alarm. Practice that for a week or two and then start setting the alarm for 9:20 and get up then. (The trick is to actually get up and not linger in bed though ;)
Oh, and wake your boys up too at the same time as you so they can start adjusting. It will be pretty much impossible for them to adjust to the 3+ hour difference suddenly in August.
Good luck!