I've had a hard time with my daughter too, who is now 14 mos. and still sleeping in our bed, and up until about 3 mos ago, she would still nurse every few hours and I wasn't getting much sleep.
Some things you can try - wear a bra to bed so your nipples are less accessible. At some point, the need of nursing may be surpassesed by the comfort of it, so making it less accessible will (eventually) discourage and wean her from doing it so often through the night. Just make sure she's getting enough food during the day and gainining an appropriate amount of weight, and know that you'll need to be patient - this could take a few sleep deprived days, or a few weeks, or even a month or two, but it will eventually help.
Also, you did not mention if you have a significant other/spouse/parent/partner with you or sharing the bed with you and your daughter, but if you do, you might consider letting your partner take her to bed and sleep with her or put her in her crib, while you sleep somewhere else. This is a process that would also take some time - from a few days to a few weeks. Your partner would want to establish some sort os sleep routine - like, she nurses with you, and then your partner takes her to your room and cuddles her, and maybe reads a book or plays music, or gives her a nice warm bath, and then puts her down, and stays with her until she falls asleep, and comforts her when she wakes up. This also requires some patience and commitment, but it is much less harsh than letting her "cry it out", because she is not being abandoned and even though she won't like it, she will still be with someone who loves her.
I couldn't get my hubby to cooporate with that last suggestion, so our "little trouble-maker" is still in bed with us. But it was at about the same age where I was getting really burnt out, so I understand. There are other suggestions at www.askdrsears.com, so if these don't work, you might want to give that a shot :)
Good luck!