Hello, I'm currently upgrading my old gpu (http://h20564.www2.hp.com/hpsc/doc/public/display?docId=c02681290) <-- this is my current pc. To a GTX 970 or though I have been told I would need to upgrade my PSU in order for the GTX 970 to work. So what cost effective and not to exspensive PSU from this list preferably since I live in AUS and I wont have to pay for delivery (http://www.austin.net.au/shop-categories/psu.html) what would work? Thankyou experts!