sometimes if people miss the first sweet spot they'll get a second wind and be up too late. i'm one of those people. if i go to bed at 9:30 i'm fine. if i wait until 11 i can lie there for hours.
maybe you need to wake her up early (i know, it sounds horrible) so she's tired for bedtime. there's a great book that folks on the forum have recommended about this...sleep begets sleep. i stayed up too late last night so i can't remember what it' called...
another option if that doesn't work is to get a nanny for her instead of daycare for dec. you could get her accustomed to the nanny then she can sleep as late as she needs to and the nanny will be there when she gets up.
i agree though that whatever you do you do it soon.
good luck! and welcome home.