Transitioning a new baby - having a rough time!

[gravy_train]

I started transitioning a new baby into my daycare last week and she cries constantly. I wish I was exaggerating but this little one cries from the time she is dropped off until the time she Gets picked up. I suspect that she is held all day at home as she follows me around all day, crying, with her hands held up for me to pick her up (which i can't do all day because I feel like that is encouraging the behavior and I simply don't have the resources). I sent the family a list of things to do to help with the transition (getting her on our schedule, teaching her to play independently, etc) about two months before her start date and feel like I did my job in that regard.
Since she started I have noticed that the other kids are very 'on edge' and have become clingy. I guess my question is what do you think is a reasonable amount of time for a 12 month old to transition into daycare? The first child I ever had in my daycare was also a very difficult transition (it too about three months for her to get trough the day without crying) and I am definitely not prepared to go through that again. I have transitioned other children into care since then and it has gone very smoothly.
Oh I should also note that she has only been here a week, so I know it's still very early on but I want (need for my own sanity) to put a timeline on this so that I can make it through!!!
Thanks for your positive ideas and thoughts everyone!