The following website offers some predictions on aurora australis visibility:-
http://www.aurora-service.net/aurora-forecast/
From this page, it would seem that persons at Sydney latitudes would be best to look around the beginning of nightfall on Friday (0900 UT; 7pm AEST).
The Kp 7 event on the 13th is unfortunately due midmorning (10am).
Regards,
Tony Barry