Ah, that really sucks.
Your teacher should really know how it's formatted as it's one of the toughest part of Japanese SL. My teacher is a VCAA examiner and will be examining this year. This is what will happen:
1. You will enter the exam room. They will ask you for your name.
2. They will ask you for your VCE number. You say this part in English. Your number will be on the slip.
3. They will ask you for your 特別研究. This is so that they don't ask questions about it in your general conversation.
4. The general conversation will start.
5. After seven minutes, they will stop you and move onto your special study. They will ask you to talk about your special study. Here, you do your one minute introduction.
6. They will start asking you questions based off your introduction. The biggest two question they will ask is: what is _____? What did you understand from (resource)? You should have more bad points than good points, because you need to come up with solutions.
If you give me your specific topic I can think of some possible questions. Good luck!