I'm so sorry to read your troubles. It's so hard to hear them cry and you feel so helpless. Especially when you're both sleep deprived. Sleep is so important for the both of you.
Does she have a bed time routine? I swear by my daughter's routine. I try to make sure no tv at least 1/2 hr before bed time. This time is usually play time: sing songs, dance, read books, ... whatever. Then I tell her we need to get ready for "nite, nite" so it's time to take a bath (sometimes whether she needs it or not). After bath, I speak to her in whispered tones always very softly letting her know it's time to settle down and then I put lavender lotion on her. Then scent is suppossed to help calm them down, whether this is true or not I don't really know, I just know what's working for my daughter. Then I tell her it's time for "nite, nite" and we go into her room and with the lights low we sometimes look at a book or I'll just rock her and speak softly about the things she did that day. Now, I will say she has a dolly and blanket that she's very attached to that she's holds onto immediately after her bath and that helps a great deal. The build a bear idea may be a good one to try to get her attached to a "friend" to go to bed with. Then I let her take a book or some small favorite toy to take to bed with her to help her relax while she's trying to go to sleep. I do the same thing when I go to bed: I read a book to help me get sleepy. Then I kiss her good night, tell her I love her and that I'll see her in the morning and I leave. She eventually puts herself to sleep. Sometimes she's asleep in 10 min, sometimes an hour. But she doesn't call for me. This is a routine she's had since infancy. You might want to consider picking up a book titled "Healthy Sleep Habits, Happy Child". It helped me to better understand her needs and what was happening with her.
All in all, I think a consistent bedtime routine and comfort items, whatever they may be, are keys to smooth bed times. Also, don't stop nap time!! Sleep begets sleep! I swear my daughter sleeps better at night when she's had a nap, even if it was only for 1/2 an hour. And if she doesn't sleep during nap time, she at least needs some quiet time ... and so does mommy.
Anyway, I hope this helps.