I'm still running a 2600k in one of my rigs, and know that is still really solid, so as "setter" said; you're left with it only really being worth your while to upgrade your GPU, but at a £200 price point for a new card you're not going to see much improvement. Don't be pulled in by the perpetual model number creep on GPU's since except for the high end cards, real world improvement in FPS return can be minimal between iterations. (Some are even the old cards merely re-badged!) I would only bother if you could increase your budget, possibly as suggested by selling your current card. Otherwise I'd save the money for a better card later.
tl;dr CPU is fine and a new £200 GPU is not worth your while.