Multiple domains, targeting a specific country

I’m a developer taking charge of New Zealand based company site.

Their main domain name is for example (not real)

They now wish to make a big push on the Australian side of their business, to focus on it even more than New Zealand.

They have purchased and an abbreviated .com i.e. At present all 3 domains point to the same website.

The goal is to get highly ranked in google when someone in Australia searches for ‘it services’ or ‘it services australia/melbourne/sydney etc’

Could anyone offer advice or critique my thinking on how to achieve this:

  1. moving to the .com would be best. Would this be correct? They wish to target AU but not exclude business from NZ and other countries. And their main office is still in NZ but they have a branch in Aus.

  2. is it damaging to have all 3 domains pointing to the same website? Would it be better for and to 301 redirect to the .com?

  3. i’ve read that server location matters, would it be worth moving to an AUS host or simply specifying geo-location using google webmaster tools?

  4. obviously adding more content to the site that includes info on their australian operations will help SEO, as will getting linked to from Australian websites

Any advice appreciated.