Processor: Intel core i5 4670K
Motherboard: Z87 Msi MPOWER.
RAM: 8GB PNY at 1600Mhz
Hard Drive: 125gb Kingston SSD and 2tb Seagate HDD.
Video Card: Nvidia GTX 760 EVGA 2GB.
Power Supply: 75O watts, FSP Group.

Hello.

What should I upgrade If I want to run smoothly future games like The Division, The Witcher 3 or Battlefield Hardline?
Currently my FPS in Battlefield 4 is from 60 to 80, (except in firestorm)

I'm thinking on buying another GTX 760 and use it in SLI mode with the one I have, talking about the processor I was thinking on a 17 4770K, but it seems it wouldn't improve much; unfortunately I can only upgrade one component.
So, what do you guys think?