There are a few shops in the city that may or may not have stock of the films you are after, such as Foto Riesel and Ted's Cameras but your best bet would be to call/email Vanbar Imaging and go pick up the film when you get here. It's a 15 minute bus ride from Town Hall.

Vanbar Imaging (Camperdown, Sydney)
http://www.vanbar.com.au/Alocation/
tel: +61-2-95505833

Use the following website to plan your bus ride;
NSW State Transit Trip Planner;

http://www.131500.info/realtime/default.asp


As for getting your black and white film developed while here, the best option for quality and service is;

Blanco Negro
http://www.blanconegro.com.au/
44-54 Botany Rd,
Alexandria, NSW, 2015
Sydney, Australia
Ph/Fx: +61-2-9698 4552

...and if you have any further questions it might be better to post your questions in the Australian APUG regional focus group;
http://www.apug.org/forums/forum214/

Also have a search there to see what others have posted... most likely you will find useful information relevant to your trip that has been asked previously.