From 2009 to late 2014 I gamed on a non-OC'd Core 2 Quad (at 2.4ghz), and an Nvidia GTX 260. This statement might make some of our fellow techies a bit sick to their stomachs, but not everybody is rocking 3 monitors at 1440p.
When I built my 4690k system, I gave the Core 2 system to my younger brother. He is using it to this day to play steam games. The only thing he switched out was the HSF, because the stock one stopped working. Everything else is pretty much as I left it...
So IMHO you have A LOT of life in your rig barring some unforeseen advance in graphene tech that allows us to see 30% increases again. Ride it out, and throw in a new GPU as needed.
Just my .02. I'm almost as at the "Virtual Larry" level when it comes to fondness of old/budget tech however. So my opinion will vary wildly from the guys running custom water cooled 3 way SLI 980 rigs (which I also happen to think are awesome).