Oculus Rift Upgrade Path

[Sev7enZ]

I am currently saving up for my new Oculus Rift gaming rig and I while I currently have a decent rig, I know that I will need to upgrade a few things. Im also looking for a good affordable case.
Here are my specs:
Motherboard: N-Alvorix-RS880-uATX
CPU: AMD Phenom x6 1045T
RAM: 8GB DDR3 PC3 10600 MB/s
GPU: Sapphire AMD Radeon 6850
HDD: 1.5TB
PSU: 300w

 

[Sev7enZ]

The build doesn't have to be specifically for the Rift, I just want some help with affordable upgrades to my older rig. At the moment I'm planning on adding another 6850, upgrading ram to 16GB, and getting a 700w+ PSU.