Given this information, I believe that you could be looking at an ATAR between 93 and 95. Your position in Chemistry and Science Extension seems favourable and is likely to make a positive contribution to your ATAR. This would also apply (although probably to a slighter lesser extent) to your performance in Physics, Software Design and Development as well as Mathematics Extension 1. It is therefore important to maintain thorough preparations as you approach your HSC exams, which will hopefully enable you to perform at a similar standard and, if possible, improve so that you can maximise your chances of achieving your ATAR goal.
On the other hand, English Advanced and Mathematics Extension 2 appear to be your lower performing subjects. Because of this, you may wish to consider placing additional focus on your preparations for the HSC exam of these two subjects, particularly your English Advanced HSC exam, because this is the subject that will definitely count towards your ATAR despite the number of units that you are taking. On that same note, the fact that you are taking 13 units is likely to benefit you since whichever your lowest performing 3 units worth of subjects end up being (with the exception of English Advanced as mentioned), the negative effect that they would have on your ATAR will be negated. Depending on your performance in your HSC exams, you could potentially exceed this estimate.
I hope this helps!