So I live in Australia and I've been trying to find out where I can get a hold of the instruments for rock band 3 (the game itself is easy enough to get). I haven't been able to find them anywhere locally though I'm told they are available in Aus but at stupidly high prices. A friend recommended the Barnes and Noble online store but they didn't have the Xbox version of the drum set, which is the part I'm most interested in. Amazon is a bust because the drums alone are like $250 plus its being sold from individual sellers instead of amazon itself so they don't post internationally.
 
So my question is: Does anyone have any suggestions for where I could import the RB3 instruments from, specifically the pro drums?

Well... 
 
From what I understand, there really are no "RB3 Drums". The basic RB3 drum set is the same hardware as RB2. The only difference is the cymbal kit. I think they sell them together and label it as RB3 drums, but if you needed to, you could just get the RB2 drums + either the 2 or 3 cymbal pack. Maybe you would have an easier time going with the latter option and finding those separately.

I don't think the RB2 drums were released in AUS. However I'm quite sure JB-Hifi sell the RB3 drums, cymbals, keys, and pro guitar.  
 
If your looking for them on the cheap look around for The Beatles: Rock Band - if there are any boxes left they may be at clearance prices. You would have to buy the whole kit but I've seen it pretty cheap here in NZ.

 Wait for amazon to get them back in stock.  
 
I did a fair bit of running around a few months ago trying to get a decent set imported to Australia (and was ultimately successful). Amazon is really the only way to go, but only when you can get the instruments directly from amazon. There is no other, cheaper method that I am aware of.

As a general indication i paid $419 US (Including priority shipping) for the pro drums (with cymbals), a fender mustang pro guitar and the keyboard.

The Beatles Kit = RB2 Kit = RB3(+Cymbals) 
 
As a UK resident, I had to import my RB2 drums from the US. I recommend eBay if you really have your heart set on a RB3 Kit, but yeah, they are just the RB2 Kit with the new cymbals for the Pro mode. Maybe import only the Mad Katz cymbals and find a used set locally?