Looking to upgrade my Phenon x ii 965 system, help?

[Bryben]

I am looking to upgrade my current setup. Wouldnt mind going to an i5 setup but thats only if its really worth it. another option is to cannibalize my PC and buy budget parts to build a second pc for my gf, and keep one for me. My budget is 600$ max (as in no more). I am good at finding deals however, so a little over is not bad. FYI I have a 120gb intel ssd not installed atm.

Here is my current setup:

AMD Phenom II X4 965 Black Edition Deneb Quad-Core 3.4GHz Socket AM3 125W

ASUS M5A97 R2.0 AM3+ AMD 970 + SB950 SATA 6Gb/s USB 3.0 ATX AMD Motherboard

EVGA 02G-P4-2678-KR GeForce GTX 670 FTW 2GB 256-bit GDDR5

G.SKILL Ripjaws X Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)

2 x Western Digital VelociRaptor WD1500GLFS 300GB 10000 RPM 16MB Cache SATA 3.0Gb/s 3.5"

1 x Western Digital WD Green WD5000AADS 500GB 32MB Cache SATA 3.0Gb/s

Samsung DVD-R/RW CD-R/RW

Cooler Master GX - 750W Power Supply with 80 PLUS Bronze Certification

NETIS WF2113 300Mbps Wireless N PCI-E Adapter with 5 dBi High Gain Antennas

Antec DF-85 Black Steel Full Tower Computer Case


ANY help is welcomed Honestly this all started by me wanting to build two budget small form factor steam boxes for me and my gf, but as with all things upgrading is probably easier, otherwise I would just sell off my PC. Was just wanting to replace my ps4 as my daily for gaming and use.

 

[Bryben]

Ok bought
ASRock Fatal1ty Z97 Killer LGA 1150
Intel Xeon E3-1231 v3 Quad-Core Haswell Processor 3.4GHz 5.0GT/s 8MB LGA 1150 CPU

What else could I do?