Well, you could put her back in the crib for a while, and see if that helps. You could also try talking to her about what is scaring her - Will a night light allow you to stay in your bed? Will a rail on your bed help? Once you get an answer, implement that. You're daughter may be able to verbalize what is bothering her, which will help you find a cure. Also, giving her some say in what happens will probably help her feel like a 'big girl', and will help her want to comply.
As to getting out of the bed - you have to lay down the law. With my daughter, we were lucky that she likes to have the door open. We told her it would stay open as long as she stayed in bed. It took one night of her getting out of bed, and us closing the door when we put her back in, before she sort of got that part.
But i do find that if we bend even a tiny bit (like letting her into our bed before our appointed 'wake up time', even by half an hour) makes things worse and worse instead of better and better. So you really have to suck it up and stick to it even if it is hard.
The bad news is, i don't think this ever works painlessly, and it will take a little while of not sleeping for it to workout. The good news is, it almost always seems to take effect within a few days, and then you get massive pay offs after the fact.
good luck!