This is my build so far http://au.pcpartpicker.com/p/r3hnYJ. I want to have a graphics card that is powerful and keeps cool and also last me a few years (2-5years)
Well it depends whats the current psu you have. A 390 is a good choice 390x an even better one the 980 would the next step up from a 390x/fury. But it's out of your price range. If you have a lower watt psu then you want to stick with a 970. What kind of power supply do you currently have?
i'd get the windforce 970 i don't know what the tax/shipping rate is in Australia but this is your best bet, though any of the other brands are good as well i just like gigabyte.
For under $350 USD your best option is the 390. As long as you have the power supply to handle it, you'll be fine. If not, the 970 is a good choice as well. To clarify: 970<390<390x<980<Fury<Fury X<980Ti.