Ahhh .. some sanity, or lack of, in a world of non sleepers! I have to say it's doing my head in, and 4 hours sleep for me the other night was just NOT on!
Hmm .. anyway, off track.  Up until Amelia got a cold, then an ear infection, and now popping 2 teeth out, she has been a GREAT sleeper.  In the past week I've been up at least once, usually more, each night.  Sometimes she is awake for 2 hours.  The other night she was up 2 hours, asleep for 40 mins, awake for another 40.
Last night she awoke at 12, went back to sleep by 12.30pm while being cuddled in a blanket, then awake 10 mins later for another 40 mins.  That was a good night.
This is what I'm doing, and maybe you could try if you wanted:
She is going to bed with tights & PJ pants on.  Plus a wool and cotton singlet underneath her PJ top.  I have taken to putting a wool blanket on the TOP of the bottom sheet for extra warmth.  We have a heater going all night in her room.  She has one wool blanket on top PLUS a cotton duvet quad folded.
I have just discovered (well, pretty sure) she is scared of the dark, so the past 3 nights, we have had the hall light on (the nightlight hasn't been used in so long it needs a new bulb).
Last night, even though she felt warm I decided to pop a cardigan on AND put the hood up - it did the trick!
Good luck!