PC-console building

[Captain_Tom]

Sharu said:

Looking on the unending flow of good exclusive games on 'nextgen' consoles aka PS4/X1 I made a desision to put my PC in a decent form and start playing 3rd party games on it. 
So could anybody tell me what kind of machine will I need to play latest PC games with a comfort?
I will play it on my old Plazma HD-ready TV via HDMI and x360 gamepad, so I don't need it to be 1080р on ultra.
1280x720 with 4xAA and 60 fps on high will be more than enough for me.

My current setup is Intel Core Duo E7500, 4 Gb of Ram and 1 Gb AMD HD6800. 

I feel that I need to up my RAM to 8 Gb and change a videocart to smth Nvidia's. 

Any help/advices will be appreciated!

R9 290 is the best price/perf right now, but otherwise I don't know the prices of cards in your country.