Advice for best upgrades / route for rebuild

[Qwiso]

Current --
MSI Z77A-G45 LGA 1155
i7 2600k @ 4.20GHz (Corsair H100i)
EVGA GTX 760
8GB Kingston HyperX 1333MHz
Corsair 64GB SSD -- Win 7 Home
Kingston 128GB SDD -- Games
500GB -- Storage
Corsair TX 650W

Where do we go from here? My budget is about $400 so I want to make the most improvement

I believe that would be made by upgrading CPU and RAM. My 2600k can handle 1600MHz after O.C. but we're blowing past that speed fast.

I'm looking at immediate improvement and a long-term (2-3 months) plan to rebuild the whole rig. Appreciate any suggestions!

 

[IntelTurtleFan]

Upgrade the graphics card to a 970 and use the remaining 100 dollars to get a nicer SSD or just save it.

PCPartPicker part list / Price breakdown by merchant

Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($97.98 @ OutletPC)
Video Card: EVGA GeForce GTX 970 4GB Superclocked ACX 2.0 Video Card ($316.99 @ NCIX US)
Total: $414.97
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-06-12 02:29 EDT-0400


Storage: Samsung 850 EVO-Series 250GB 2.5" Solid State Drive ($97.98 @ OutletPC)
Total: $97.98

Video Card: EVGA GeForce GTX 970 4GB Superclocked ACX 2.0 Video Card ($316.99 @ NCIX US)
Total: $316.99