If you are nursing try a family bed. You can lay down,snuggle and nurse and both fall asleep. After a few days you get in sync with each other and before she wakes all the way you will sense it pull her close,start nursing and be asleep again. This was my lifesaver...kept me from total sleep deprivation.
It maybe depends on what time she last eats for the night.... I use to feed my daughter at about 9 ish or 10pm and put a little cereal in her milk. She would sleep all night and i would have to get up and feed her during the night.
Is it possible she isn't getting enough to eat? Or is gassy? tummy issues? I was a rocker mama. I sat in a rocking chair with my girls, and hummed or sang to them. I think the gentle sway motion lulls them to sleep.
The vibrating swings/seats are a good idea too(they didn't have those when my girls were babies. ;) lol just be patient, u will find the right nitch for your little one.
My oldest loved to be swaddled. He would go right to sleep if he was wrapped all up. My youngest I would bring into bed with me although I still didn't sleep well because I was always worried I would roll on her. Good luck and hopefully things will work our quickly and you get some sleep.