What graphics card should i get for my system?

[Daggerfall948]

So I have just built my first PC but I haven't got a graphics card yet as I don't relay know what is appropriate for my system and what I can get for different price ranges. I'm going to be using this for gaming mainly so i would like to play on -low-mid graphics with a descent frame rate.

This is the specification of the PC so far:
AMD FX 6300
4GB RAM 1600MHz
Gigabyte GA-78LM-USB3
Powercool 750W Modular PSU
Casecom CB-341 Black Mesh Mid Tower ATX
Seagate ST1000DM003 1TB Barracuda HDD

my budget is £60 - £150 if you tell me what's a good graphics card in £60 - £80, £80 - £100, £100 - £150 that would be great.

 

[electricfirebolt]

HD 7870, Something around that.