Very difficult 3 yr old girl please help!?

My daughter will not potty train, she will sometimes go #1, but it is not regular, she NEVER does #2 on the potty. She screams and yells at my husband and i all the time, says she is going to hit us, we never hit her. She NEVER listens or does as she should or is told. She is so head strong and willful. We are at our wits end. Are there any books or advice anyone can give. I really don't know what to do? (She wears underwear all day, can hold her urine for up to 8 hours and at night we put a pull up on for bed. SHe will SCREAM and CRY on the potty like she is scared but will saty on it and then when she uranites she stops crying and is over it? I'm so sick of this....it's been going on for 2 months! I can bearly step out of the house because she wont go on public toilets or with out her potty seat...and that is getting too small) I'm so fed up. Thanks for the help.