Frustrating!

So Sarah woke up this morning and as soon as she woke up she started going into this story of Batman and Mr.freeze; but it ended with Batman telling Mr. Freeze "I guess your frozen". It was really strange and funny; who doesn't love Batman?
Later on was not as funny when I had been trying to get her ready for school for about a half hour. Finally I say "Sarah, I've been trying to get you ready for a half hour and you have done nothing to help. Your lunch has been made but other then that you have been playing all morning and not listening at all." I guess my anger had gotten out of hand and she probably saw my nagging as an attack. So she looks at me and tells me she's going to punch me on the nose and what do you think she does? So I tell her that she shouldn't hit and then she hits my arm, I tell her that she's being very selfish and walk away. I walk away fuming not wanting to snap on her. So when I get back she goes in to this story of a little boy sitting on his sister and that he shouldn't do that because people wont like him. So I say "Sarah what if this little boy punched his mom on the nose; would that be nice?" She said no and that was the end of it. So before I dropped her off at school I told her to talk it out before she get's so mad. She has never hit any one at school yet but I fear that it will happen if she keeps this up. Her teacher talked to me yesterday about how she's the only kid not listening and following along with the rules. So we're trying to make sure she is paying attention when we are talking to her but so far I'm not having much luck. I just need to be patient with her and myself.