Hi Amy,
I have heaps of trouble with EW's and pretty much got the solution through the support for EW's sticky thread on this board. If you look back through the history of that thread you'll see what's worked for others and what hasn't.
What I can say is that since you are needing to put your LO down early at night, your EW are prob not real EW's they are just the prodcict of any early night. 6.15am to 5am is nearly 11 hours which is a solid nights sleep, even this can be said for 10 hour nights too. It is very common thing to happen in the 2 to 1 swtich, dome LO's just won;t sleep in when they have an ealry night. I would say that once LO gets used to one nap and the longer activity times you can stretch the bedtime to a little later at night and also get the nap time a little later. Hopefully later wake-ups will follow suit.
I can post some links to my old threads where I got some good advice if you like.
Eloise