potty training nightmares

So I have been trying to potty train Marley. Last spring I bought her a potty chair, she loved to play with it, just not poop in it. She went in it a few times last summer, then nothing. My friends said, just get her some pretty panties, she won't want to get them dirty, so she'll use the potty. So I got her the pretty panties, and as soon as they were on, she peed all over the floor. We got the pull-ups and I put her in sweat pants so when she needed to go, she wouldn't have to wait on me. Then I vowed to sit her on the toilet every hour. We even had a chart where she put stickers on it every time she went. I set the kitchen timer and every hour she went, for about three days. After the third day, she refused to even go in the bathroom, let alone sit on the toilet. I decided to give her some more time. I got 5 video's at the library about potty training. There was one about a bear, (she loved it) There was one that was anatomically correct, there were ones just for little girls. We watched them all! She said "Mommy, I want to wear big girl panties." So we went to target and got the most beautiful princess panties ever! I got her the kando wipes, and a new potty seat. On the way home we made up a song called "I don't need no stinking diapers!" And we got home and put on the beautiful Cinderella diapers, and she peed on the potty, all day the panties stayed clean. We decided to go visit Nana and Grandpa. She even pottied at their house, no problem. Then I turn my back for a second, and there she went all over Nana's kitchen floor! I don't know what else to do! I need serious help! Please someone help me! Are there any potty-training camps, where you can send your child to have someone else to train them?