Given this information, your performance seems consistent with an ATAR no lower than 97.5 and up to 99. Your performance in most of your subjects is evidently of a high standard, meaning that they are highly likely to make a positive contribution to your ATAR.
English Advanced and Mathematics Extension 1 appear to be your highest-performing subjects. To maintain this standard and achieve favourable HSC marks, you should prepare for your HSC exams according to the same study strategy that you have adopted up until this point (which has been quite effective).
The same can be suggested about English Extension 1, Physics and Engineering Studies, although perhaps to a slightly lower extent. Based on this, you may wish to consider putting a bit more effort into your preparations for the HSC exams of these subjects, which will hopefully allow you to achieve your target HSC mark in each subject.
Mathematics Extension 2 appears to be your lowest-performing subject. Of course, the fact that you attend a high-ranked school implies that you are part of an academically capable cohort (which in turn suggests that your position may be somewhat favourable), as opposed to being ranked the same at a low-ranking school. With that being said, you know the specific aspects of your position (including your strengths and weaknesses) in this subject more than anyone else. I would simply recommend preparing for your Mathematics Extension 2 HSC exam to the best of your ability, so that you can maximise your overall result in the subject.
I hope this helps!