Sarah, this is what worked with Ashy when she was about 2 1/2 and i was so sleep deprived it was my last option. (I know bribery isn't the best answer but it worked and that was all that mattered to me at the time)
Each night before bed I'd put a few m&m's (or some other little treat) in a little bowl. I'd tell Ashy if she slept all night without waking up mummy she could eat them in the morning. If She kept waking up we'd put them in the cupboard for the next night. After a few mornings waking up and not getting to eat the M&M's cause she woke up in the night, she finally started sleeping though.
To this day (she is 5) if she is having trouble sleeping for a while we still do this, but the reward has changed. Recently it was she's get a diamonte on a fingernail every night she slept through so that to have all her nails looking funky it meant 10 straigh nights of decent sleep

Another option was to put the blues clues fold out couch in my room and let her sleep on the floor next to my bed for a while. I didn't like the idea of her sleeping in my room at 2, I wanted her to learn to stay in her own room, but like i said before, at the time it was the ONLY thing that worked and I needed the sleep. Same as Zander, she just wanted to know I was close by.

Hope things get better Sarah!