What would be the best way to upgrade?

APU: AMD A10 5800K Black Edition

MOBO: MSI FM2-A75MA-E35  

RAM: 2x4GB Patriot Viper Extreme DDR3 RAM 

PSU: 500W 

This the the build that I am currently using for gaming and so far it can play anything I've thrown at it at low to medium settings for recently released games. I would like to be able to play games at high settings and make this computer last for at least two years and be able to handle any games that come out. What would be the most cost efficent way to upgrade? 

Video card for sure - Whats your budget?

Definitly vid card. If im correct HIS ice-q 7870 is around 200 usd and AMD has a promotion where u get a bunch of free games like tomb raider and the new bioshock for free with it.

I 2nd the 7870 2gb edition with dual fans (what ever make/spec you want)

Get a dedicated GPU. And like the onthers are saying, go AMD. They have some amazing deals right now!

I'm looking to spend about $200. A dedicated GPU was what I was considering. I just wasn't sure which one would be best for me. Thanks a lot. 

the best dicreet graphics you can afford!

for the 200 price point as i said a bit ago the 7870 is ur best bet. it will run most everything at max on 1080p and for the one i recomended i believe there is a benchmark video about it.