Upgrade for a 660 TI?

Hey guys, I'm really at a loss here. 

I want to upgrade my GFX card since its only a 660 Ti right now and it has begun to struggle on some games. 

I was wondering what I could do to upgrade it, I was hoping nvidia would release some new cards this year but nope. 

What is everyone's recommendation on what I should buy to upgrade from a 660 ti, I was thinking SLI but the 660 ti is out of production and used cards are still expensive for being used and cant trust it. The 760 is the same thing basically, I dont know what I should purchase to upgrade

Budget around $250-$300

My specs:

Fx 8350

16 gb ram

660 TI

Asus sabertooth mobo

$300 + $$$ from the sale of your 660ti then buy a r290 or gtx780 (if you can find one at a dirt cheap price).

buy a r9 280 or a 280x there around 300 dollars and there really good but the 770 is also there and the cards are basically same performance. you probably don't need a 780 or 290 but if you can go with them why not but the 280 and 770 are enough to max out all games at 1080p

if you could sell the GTX660Ti for arround a $150 you could indeed look for the higherend cards R9-290.

But if not, a R9-280X would be a great choice.

http://www.newegg.com/Product/Product.aspx?Item=N82E16814121803

I would grab a 280X over a GTX770 2GB, anytime, because the 280X is cheaper, and has more Vram.

Good suggestions, I would however go with the 770 because nvidia drivers are king and I have read a lot of people have artifact issues with the 280x. 

Which 770 do you recommend seeing how EVGA has about 300 different cards to choose from and I cant really tell the differences in them.

Is the 770 really that much of an upgrade from a superclocked 660 ti though? 

And I would probably need to upgrade my PSU since it's only 600w, what 770 do you recommend?

 

thanks