That's a tough one for me. However, 1 to 7:30 is a really long time. My ds is usually asleep between 7 and 7:30 and he is usually up fromhis nap at 2:30 to 3:00. I am stuck with the same problem but I also know that ds is teething and now has a cold. He is streaming from the nose and at nap and night time he rubs his mouth and shows me where the "ouch" is. THis is with medication. Sometimes it is really clear as goes right back to sleep after some teething gel. Other times not. Last night he was up 5+ times and early for the day. The thing is - he is happy as can be during the day. I have taken him out of his crib after he has woken early from a nap, is still tired and not fighting to get up, but unable to get back to sleep from discomfort. Once we get out of his room, he gets distracted by the exciting world and you wouldn't guess there was a problem.
On the other hand I have seen the overtiredness creep in very quickly and have found that it can be so hard to get back on track. I would definintely try for early naps and bedtime and see if that helps. You may also want to check for teeth. I know that teething for ds generally makes him restless, regardless of the pain and belly discomfort he has.