Hi M.,
I see you already had a lot of responses so i will keep it short. I also struggled with my son waking up early. in summertime it would be 5am and in winter around 6am. i tried everything like getting him to bed earlier which didn't work for him. he would be awake for more than an hour before falling asleep and still wake up early. I red 'healthy sleep habits happy child' and i even consulted doctor Weissbluth of the northwestern children practice who wrote the book and has its practice here in chicago. nothing worked.
Than, i came across a book which i bought for our 2nd child who's on the way to make him/her sleep through the night by 6 weeks. to make a long story short. she advices to make the bedroom so dark that you won't be able to see you own hand before your eyes. there should absolutely come no spark of light through the windows because around 5am children get in a lighter sleep and can wake up from the tiniest bit of ligth.
i wanted to give this a try and before spending 100dreds of dollars on shades and curtains i went to home depot and bought thick contractor waste bags and a roll of tape. I taped all his windows and doors. 1st nightr he slept half hour longer. i checked his room and there was still a tiny bit of light coming through the windows and underneath the door, so i taped that too. 2nd night he slept till 6.30!!! hurray! so now i'm looking into a way to finance some roomdarkening shades and curtains because it the bags don't look so nice.
he also goes to bed a little later, he used to go at 7.30 but now it is 8.30 and i do not let him nap longer than 3pm, so about 2 hours. my son is 2 and still needs his nap but maybe yours doesn't and put him to bed at 7pm.
well, story still got long but i wish you luck and i wouldn't bombard your child with too much change. try one thing for a week (also advised by dr weissbluth) and see what it does because they need at least 4 to 5 nights to adjust to a new schedule or change.
Good luck and let us know if you've made progress and congrats with the new baby!
M.