C.,
10 to 18 months is the time for separation anxiety. I would suggest spending a lot of one on one time with her for about an hour before bed time, just cuddling and playing together. And then, when she wakes up at night, give her comfort by rubbing her tummy or her back and then shush her for a few minutes and say "Go night night" quietly and gently.
The reason she goes back to sleep with you is b/c she is comforted by your touch and scent. However, unless you are willing to allow her to stay in your bed for a long time, I would try and stick to your guns for a few weeks until she realizes that she must stay in her bed. Give her comfort, but be consistent in your decision, whatever you choose, so you don't confuse her.
Don't fight her as if there is a battle to be won, just be her teacher and teach her the rules and that you are the authority who enforces those rules. Don't take the easy way out and throw the rules out the window simply for your temporary comfort. Parenting takes a lot of time, effort, and discipline (self and child). If you know how you want things to be, then you will need to make some amount of temporary sacrifice in order to get it done. But the results are well worth the time spent.
Take Care,
T. (mother of 4)