will I be able to work this out without buying something extra? and if so what do I need to buy?
That gpu takes 2 6 pin connectors, the last photo in the PSU pictures shows this second from the left wire with red plugs. You have what you need. Good luck
Your power supply should have the cable it needs. It has a 6+2-Pin so that you can snap it together to form an 8 pin.
