Oh boy, I'm in this situation right now. My 2.5 year old has only ever been with me and is very attached. Like your daughter, he is fearful of other kids- he was never around them. Our pediatrician kept telling us he needed daycare/playgroups. Well, I finally got a job at a daycare simply to pay for him to go. And it wasn't fun.
I took him in a day early just to stay with him for an hour or so and then we would leave. He cried, stopped for a few minutes, cried again, and on and on. With me there! We ended up leaving after 30 minutes or so.
The first day he was in I took him in 2 hours early so he wouldn't be arriving at naptime. He willingly sat down at the table to play play-doh and I snuck out. He cried immedietly. I came back after about 45 minutes and peeked in the window. He was on the teachers lap crying. He saw me and I went in. I helped him eat a few bites of veggies but he was miserable. I read a book to a few kids and he stood and listened. I had to go to work so I left. I stood outside and listened to him screaming at the top of his lungs for me for an hour and a half. I cried my eyes out. It was so heartbreaking. Thankfully, working at the same daycare I'm able to get updates on him. Basically, he did settle down but cried off and on all day.
The second day I brought him in at naptime, as the teacher recommended as it was calmer and quiet. He went in willingly and I left right away. I heard him cry but left so I wouldn't hear it. He did much better that day with minimal crying and the teacher's even got him to play.
The next two days it snowed so we didn't go. It's Saturday now and he's throwing up and coughing. Screw daycare and their runny-nosed kids with germy hands.
No, seriously, the teachers recommended bringing in a family photo for him to look at. I went a step above and made a little photo album of us, the dog, his daddy's truck... the teacher was able to get him to calm down by asking questions about the photos.
I also took in books he liked- cars and trains are his life- the teacher said he would sit and look at them.
The real downside is almost immedietely he started crying out at night and now needs myself or Dad to sleep in his room. He did this when we moved, too, for a few weeks so I'm assuming it's just an anxiety and will ease up.
I agree with others that an hour may not be enjoyable for her. At first it may be good so she will learn you will come back but as she settles in it might be good for her to spend 3 or 4 hours there to get full enjoyment. As another poster said, just as she settles in and calms down you would be there to pick her up. Perhaps you could do the hour the first few days, 2 the next few and stretch it to 4. Give her time to experience other kids and allow you to do homework.
It's gonna be Hell but eventually it'll stop. Eventually. My fear is that this week off from daycare will have my son starting from scratch. Crossing my fingers for not though!