I feel for you! So exhausting! My son, who will be 4 in a few weeks, has had trouble sleeping ever since he was put into a toddler bed, too. I think he realized that he could get out of bed and come to me whenever he wanted, so he would wake me every couple of hours all night long. It has been going on for close to 2 years now. But, now, finally he's not waking me up at night all the time. He still will sometimes, but at least it's not every day anymore. He also used to come out of his room and mess around while I was in the shower at night and when he was supposed to be napping. He would do this on the days my husband was gone driving his semi. Nothing I did would make him stay in his room and go to sleep. I tried spankings, I tried taking him to his room silently, I tried reasoning with him (even though I knew I couldn't reason with a small child). So, finally I changed his doorknob and put on one that has a lock on it. I've only ever had to lock it a few times, and it wasn't for very long each time. Just long enough for him to realize that I mean it and he'd better stay in his room and go to sleep. Now, he doesn't come out and mess around when I'm showering or when it's naptime. Still working on the night wakings, though. I've been wanting to try the product Good Nite Light for a while now. It's a night light that you program to shine like a moon when you want your kids to be sleeping, and when it's ok for them to be awake you program it to be a sun. That way your kids know that it is ok to come out and be awake. It has lots of great reviews. We just can't afford to get one right now.
My 2 boys are in separate rooms, too. I run a box fan in each of their rooms to drown out the noises of the house so they sleep well. You could try that. Then your 1 yr old won't hear your older girl when she cries.
Hang in there! You're not alone in this battle! :) It will get better. Just be consistent and firm. Hope you get a lot of great advice to help you out, and I hope this reply helped some!
A. M.
www.homewithmykids.info
www.livetotalwellness.com/apriljm