Sydney!!!! Lucky lucky you! (although the Melburnians on here might beg to differ
) What a fantastic opportunity, it really is a great place. I had the good fortune to live in Australia for a year (in Townsville), and had friends in SYD so passed through a couple times. I hope you have a wonderful adventure.
I forget- are you in customs? If so, you're stuck- gotta get them done in the US. If not different story, and while you're waiting for the Aussies to chime in here, I'd start investigating pro shops, call them directly and have a chat. How far away are you from new boots? If you know exactly what you need then you can always order, timed for a trip stateside and hand carry them back. If you wear MK/Wilson blades you might find they are cheaper in Oz. I've gotten MK blades direct from the UK at a lower price (including the shipping to F) than I would have paid stateside; taxes and duties make a huge difference. Ultima are still cheaper than the UK brands though, even over here.
My experience in France, which has a much smaller skating community/tradition than anglophone countries, is that most people here order over the internet, and just suffer with ill-fitting skates. When you can find a skate shop (my closest are 5 hours away in Paris, and one 7 hours away in Lyon), they have NO IDEA how to fit skates, and heaven help you if you need anything other than a standard width. Also, they might not have your brand, but could have others. I can't get Riedell or Eclipse blades, but can get Belatti and Wifa for example. So you might find something new and better. Or not. ymmv. A lot of skate maintenance for me at least, happens at the rink with the coaches. They do the best they can which in my case is pretty good. But they don't have the time/knowledge or equipment for heat molding or punching out (and the local cobblers don't understand about heat-moldable materials).
So be prepared for a different culture skate-shop wise. You might find you can get what you need, but you might also find you need to get them done stateside. I'm nearing boot time myself, and if I had to buy tomorrow, would get them in the US. But I'm still trying to find something that works in France. Non-standard widths are a problem here; they don't like to take the risk and split widths seem to be unheard of. But if I can find someone to work with over here it's better for the overall skating community, and the local businesses.
Good luck!!!!