From this information, I believe that your current performance is consistent with an ATAR in the low to mid 80's range.
Your rank in Modern History and Legal Studies is favourable and is likely to assist you in maximising your Assessment Mark, which can in turn make a positive contribution to your ATAR. Because of this, it is important to do your utmost in order to maintain your position (or even improve if possible) in both subjects as you keep progressing through year 12 and approach your HSC exams. The fact that no band 6's were in achieved in either subject at your school last year, while not promising, does not necessarily mean that you do not have a chance of achieving a band 6 in those subjects since only you can determine your standard of performance through your commitment to your studies.
Your rank in Business Studies and Mathematics Advanced are also good, although perhaps not at the same standard as Modern History and Legal Studies. This means that there is definitely room for improvement. The more you can improve your rank through favourable performance in your upcoming school-based assessment tasks and exams, the better your position in both subjects will be as you get closer to your HSC exams.
Economics and English Standard appear to be your more concerning subjects, and may currently hinder your progress towards achieving your ATAR goal. Because of this, it is crucial that you do your best in your upcoming tasks so as to improve your ranks, especially in English Standard because, out of the 12 units that you are taking, this is the subject that will always count towards your ATAR, regardless of the mark that you achieve in it.
I hope this helps!