AGGH! Stop, don't do it! You really really can't go in there at 3:30 am and expect any different from her. She loves you, she's your daughter, it's a thrill to get some extra mommmy attention and time. You are reinforcing unwanted behavior. It's natural to go through sleep cycles and for a babe to wake up, but she should be able to put herself back to sleep. My also 2 year old has a pacifier to self-soothe as well as this Ocean Wonders crib side thing. Hands down both have been life savers. She's too old to start her on a pacy if she doesn't take one, but you can definitely get the Ocean Wonders thing. Part of our bedtime routine is that she hits the button to get the music going (it times out). She LOVES exerting that 'control' and the music helps her relaz herself. So when she wakes up in the middle of the night, she just hits it and goes back to sleep (I hear her on the monitor). She doesn't bother to call me. HOWEVER, we have a nanny during the week and since I have a 4 month old (we sure have a lot in common?) I keep the montior at night for the younger one and the nanny keeps it for the toddler. So my very smart and manipulative toddler has learned that if she is in 'crisis' (drops her pacy over the railing) that the nanny will get out of bed to come give it to her, comfort her and tell her to go back to bed. I tell the nanny not to do so or at least not to make it so easy but low and behold she does this anyway. But I tell you, my little girl is smart. She knows mommy isn't having that so on the weekends when I'm on duty for both babies and there is no nanny- all of a sudden there's no middle of the night crisis. She magically manages to hold on to her pacifier and to just turn on her little music and go back to sleep. (the 1x or 2x she pulled the serious crisis mode and I had to go in, I was NOT happy about it or nice/comforting but rather corrected her that it was still night night time and lay back down, etc.). She got it all right.
The other thing I want to say is that her sleep needs have diminished since she turned 2. We really have very similar schedules. My daughter would nap from about 1pm to about 4pm and nightnight was 9pm. That really works for us because during the week I don't get home until 8:30pm and would literally never see her all week if it wasn't for that. But we found that she has been staying up either most or all of her regular naptime. We still put her down for it though. What I am doing is putting her down a bit later and getting her up a bit earlier at times. For you, that's where I think you should tweak. I really can't believe she would even go to sleep all night after just 2 hours of being up. But anyway, pull up her nap times so that she is waking up from it earlier. Then she'll be more tired later. Best wishes, feel free to contact me if you'd like... N.