Roland Of Gilead :
I don't really agree with Wayfall (no disrespect intended)
Your CPU is absolutely fine. Its powerful enough to drive any high end GPU, including the aforementioned GTX970.
Your CPU will do just fine for any AAA games (depending mostly on screen res, and in game settings) but should be able to get high/ultra settings for most games.
There has been ample articles on both Toms and other hardware sites, showing that an I7 over an I5 is of practically zero advantage for gaming. If your only gaming as opposed to video editing, Photoshop and those types of things, it is pointless to get an I7.
All you really need to consider is a new PSU, but you may get by with the one you have. The GTX970 only draws an additional 40w of power, and given you don't have an I5 k version (meaning overclock-able) you could be just fine. To be on the safe side though, a good 500-550 w PSU would suffice, and give you a really good gaming experience along with your current CPU, and potential new GPU
None taken
I would just like to say that an i5 can run lots of games and I did say you could upgrade if you wanted to in the future to play the big games out there which there aren't many, really just the four I stated above.
I tried all of those with an i5 4460
-Fallout 4 played mostly fine but bottlenecked 100% in cities
-Witcher 3 played kind of fine but bottlenecked in small cities even on the lowest settings
-With Assasins creed unity it was mostly its fault for being so badly optimised but the CPU again got near or on 100%
-Assassins creed syndicate actually played rather well and only dipped a toe in 100% now and then causing framedrop now and then
All of these games need a quad core CPU with s high clock speed and at least 8 threads. I stuck an i7 4790K in and I have no issues with these games anymore. An overclocked i5 4690K would do really well with these games also.
His i5 is fine but what I'm trying to get across is that those are the games his CPU can not run playable, all the other games out there his current CPU will thrash.