A bunch of guys on the Strobist Flickr group say that MPEX ships to Australia, and the prices aren't that bad, as long as you can avoid GST by keeping your orders under $1k.
You may want to give
Zack Arias's white seamless tutorial a read, to get an idea of what might be involved with some kind of Strobist home studio set-up.
Speedlight-wise, the MPEX Lumopro LP120 is probably to be preferred over a Vivitar 285HV, if you can afford it. The 285HV (and its current incarnation, the Cactus KF36) doesn't swivel, is missing the 1/8 power setting, and its PC port is non-standard. The LP120, in comparison swivels, tilts, and zooms, has a 1/8 power setting, and uses not only a standard PC port, but also a 1/8" mono jack, and has a built-in optical slave.
Using a cheap manual-only flash like the LP120, however, only really makes sense if you're
only planning on using the flash off-camera in a studio-like setup. It's still useful for on-camera work, but if you're, say, event shooting in a run-and-gun manner (say for shooting weddings or photojournalism), it may make more sense to get a Canon, Sigma, or Metz speedlight for e-TTL capability as well, so that the flash unit can do double duty both on and off camera. In that case, a 580EXII or 430EXII might make more sense.