Sell GTX 570 and buy a new GPU?

Esofam

Honorable
Nov 3, 2013
2
0
10,510
Hey folks.

So I built my first gaming PC about 2 years ago and it's lasted me well up until the latest bunch of game releases, notably Battlefield 4 which is really taking its toll on my GTX 570.
Since I don't really follow trends in hardware, I'm wondering if someone can wisdom me up with advice on when would be the best time to sell my GTX 570 and buy a new card, and which card should that be?

Currently GTX 570s are selling for around £70-80 on eBay UK, and GTX 770s are going for around £240. With the nvidia deal giving 3 free games (does this deal apply to the UK?), I was thinking of buying a new card fairly soon. I'm unlikely to play many games until at least Christmas, but how quickly will the 570 devalue further?

Thanks.