I am being audited what do i do?

as of two weeks ago i am being audited. i have filed for a with holding of 0 and i have with the written permission of the custodial parents claimed their two children. the mother of one has no claimable income, and the father of the other is not planning on filing, taxes because he is behind on his child support and they will take it all... what do i do? and will i be penalized. i efiled and i did not see a spot to put a non relative but living with me. but that does not mean i did not look very good. please help