Aug,
You were claiming you needed the visa urgently because your brother had had a serious accident - yet, when the officer was going to grant you a 3 month visa, this wasn't "good enough" because you had just had two back to back 12 month visa's? Seems to me if your main concern was getting to your injured brother, you would have been grateful the 3 month visa was issued, instead of insisting on more.
AS other posters have mentioned, getting any length of visa is not your "right", but, it totally at the disgression of the issuing country. I'm sure the Australian government has guidelines in place for it's consulate officers regarding the issuance of visas - and, it;s very likely that already having had two back to back 12 month visa's raised some flags - possibly the officer was already doing you a favour be granting th three month visa - and you got abusive with here - at least somewhat , for her to have reacted that way.
Did you visit your injured brother while you had that three month visa? Why do you feel the need to be granted yet another visa 9as you say, considering the expense, hassle, etc) considering your N-400 application should be adjudicated with 4 months or so.
Please report when you current application is returned to you.
Also, you are aware that when you become a US citizen you are still required to apply for an electronic visa to re-enter Australia?- this can be done online, no need to send your passport, it is recorded electronically, and is usually granted very promptly.