Geez, L., don't get pulled into what could potentially be the bad habits of some of the pro-co-sleepers on this site. If you truly WANT to be a co sleeper, than they're the ones to go. I have nothing against it if people choose that, but it sounds like you're wishing things were how they used to be when your child slept where they were supposed to....in their room, and you slept how you were supposed to...in yours, with no kids. I prefer to still have an intimacy in the bedroom, in our bed, with my husband, and also really cherish those hours after the kids are put to bed to spend time with my husband. My kids go to bed every night at 8, we have a great, peaceful bedtime with books and cuddling. Then, it's me and Doug's time. My kids are now 4 and 5, but when they were younger, they would go through periods now and then when they wouldn't sleep well at night. Usually it was because they'd wake up one night and since it hadn't happened for a while, I would allow it and even at times allow them to crawl in bed with me. Well, what do you know, the very next 3 nights, then you have your child doing the same thing. Not because they're "needing love" from you....it's because they were allowed to do it once, and therefore will try, try again. My kids are so showered with love, but they know that bedtime is sleeptime, and that unless they're not feeling good or something else is wrong, that they are to stay in bed and get their much needed sleep.
Having said that, if I were you, I would put her in a regular twin bed, with a rail on the side. It wouldn't be so enticing to want to get out of. Then, I would explain to her that it's time for bed and that she is to stay in bed until morning. If she comes into your bedroom, simply pick her up, carry her back to her room, and lay her in her bed. Do it everytime she does it. Don't say anything really to her, because you may find that she's still half asleep. You may have to do this over and over the first night, and maybe even the second and third, but trust me, she'll realize that she is not going to be allowed to sleep with you, and she WILL give up and sleep in her own bed. Since you've already allowed her to crawl in your bed, you're going to find those first few nights are going to be extremely repetitive and difficult, but they will get better. When my son decided to keep crawling out of bed during naptime when he was about 18 months old, I laid on the floor outside his bedroom door and peered under it. Every single time I saw his foot start to come down to the floor, I would go in, pick him up, and put him back into bed. I am not joking, I did this about 20 times that first day, it was very frustrating, but the second day I only did it 3 or 4 times, and the third day he stayed in bed and got a really good nap in. It's all about establishing your rules and limitations as a mother and then just following them.
I'm sure I'll get ripped apart by the co sleepers, but man, this poor woman heard from all but one co sleeper, and as a mother who really feels like she's got her kids' schedule perfected, I felt I needed to share the secret to a stress free (atleast at night, huh??:) ) naptime and bedtime, which is time that should be shared and enjoyed with your husband, not fighting or sharing beds with your children. Believe me, your child gets all the attention they need during the day. It's our jobs as parents to teach them good, healthy sleeping habits, among many many hundreds of other things.