I agree with everyone. Unfortunately you need to ignore her. It's hard, I know, but it really is what's best for her in the long run. Depending on how old she is, she may need to go to the bathroom in the middle of the night, which is fine, but she should go back to her sleeping place right away afterwards. Strictly bathroom business only during the night. She's already learned that if she whines, she'll get attention... a dangerous place to be if you want some sleep in the future!