I've had bad teachers like that. Is for just one class? If you are really needing to talk with him/her but can't get through...go to the principal. You have every right to ask questions and get the help you need.
Maybe you could ask her the question after class. :) or make a face of confusion(like you don't understand a word she is saying) and she will notice and ask you if you have a question. That works for me. all I have to do is look confused. :)