They come with their own schedules, don't they?
Have you tried soothing music? I don't mean those sappy lullaby CDs (apologies to anyone who likes those, they drive me nuts!) but my kids were always knocked out by Charlotte Church's first CD, or Enya, or Celtic Woman. Worked on my sister's kids too. She didn't think it would, but twin screaming two year olds and a screaming one year old were asleep within a minute of Celtic Woman starting. Awesome music! That was during a visit, and she took the CD home with her for the cross country drive. The kids insisted on having it to go to sleep every night after that, they totally wore out the CD in a year and I had to get her a new one!
Also, do you have the lights low for an hour or so before you want her to go to bed, and then turn them out when it's time for her to go to sleep? The dark triggers the release of melatonin, one of the sleep hormones. Do you rock her for a bit before you want her to go to sleep? Me, I have no problem with rocking a kid to sleep, even every night, I love cuddling them, and they learned to go to sleep on their own when they were ready. I had to rock my son to sleep every night until he was three, as he projectile vomited within 10 seconds of starting to cry hard, every single time, and cleaning up an entire room, shampooing carpet, washing all the bedding, changing my and his clothes, that just wasn't an option every night!
I've never been an advocate of the "letting them cry themselves to sleep" school of thought. Maybe for a two year old, but before that I think they're just not able to understand why this person who is their whole world doesn't come when they're scared/upset/sleepless.
Rock her slowly, play soothing music, have the lights low, slowly and gently rub her back, don't jiggle or bounce her, hopefully she'll get sleepy soon and you can get some rest. Sometimes just laying them in their bed in the dark but keeping a hand on them for a few minutes will reassure them and they'll fall asleep, sometimes even before your arm does.
Oh, and I've got tons more experience than just my two, I'm sixth of fifteen kids, have always been a "little mommy" and mothered all the younger ones to the point of one thinking I was her mommy and preferring me over our mom! I can put nearly any baby to sleep within a few minutes if they're even remotely tired. I've tried all kinds of things, and these are the most effective for me.
Good luck! Hope you get some sleep.