If you're planning to upgrade your processor then Skylake is the only thing i'd buy unless I was looking for cheaper used parts. You'd get much better performance with your GTX780 with that.

1440x2560 is bae i run it all the time on my 970 everygane i get average 45-60 fps thats on like fallout 4 tho on high. But recording that aswell will be very tough get a better core and play 1080p as a viewer fps is way better than 1440p

Well, yes, a 970 will perform fine at 1440p. However, you currently have a 780? Are you looking to 'upgrade' to a 970, because it wouldn't really be an upgrade. The 970 is basically just a refreshed 780, so stick with the 780. The only logical upgrade for you, GPU wise, would be an R9 Fury or something higher end IMO. CPU is definitely what should be upgraded first, and there's really no reason to stick with Haswell IMO. Grab an i5-6500 and a nice Z170 board and you'll be dandy.