We had 2 that would wake in the night around that age. I did as Mamazita did - they were allowed to come in and sleep on our bedroom floor. I just had a comforter down. After a while, they lost interest in it and slept in their own bed again. Sometimes they'd had bad dreams (all my kids went through a phase of this) so I liked giving them that option.
I was too tired to get up and do the back to bed thing. But that would work if you have the energy :)
She could be cold where it's been the coldest time of the year.I had one that I'd have to turn the heat up a bit because she would kick off her covers. I did those fuzzy onesies too for her. It helped. I have friends who used sleeping bags to make sure they were covered well.
My other thought is just make sure she doesn't have fluid in her ear left over from her bad cold. My kids used to get ear ache (not always an ear infection) after bad colds and it was just painful enough to wake them at night (lying down makes it worse).
Good luck :)