You should follow the advice that everyone has given you on how to handle you situation , but as far as marks goes , the board of studies is notoriously tricky to predict ...
Each year can be different ... but you are ranked in second place and if your teacher ranks you in second place to the bos and if you do better than the person that is coming first your marks will probably be swapped , if this asian person does really bad in the final exam and a lot of other people do bad then your mark may be brought down if there arent many people getting top marks , but this also depends on the state , if the whole of nsw does bad in it then the bos will think that the course was particularly hard this year and all the people who got above average will be pushed up... you just dont know what happens each year so just do the best that you can !