Built a PC at the Beginning of Jan: 
  
Spec: 
CPU: Intel i5 3570K @ 4.5Ghz 
CPU Cooler: CoolerMaster Hyper 212 EVO 
Motherboard: Gigabyte GA - Z77 - D3H 
Memory: Corsair Vengeance 8GB 
Video Card: MSI Twin Frozr III HD 7950 OC @ 1000/1575 
Sound Card: Asus Xonar DGX  
Power Supply: Antec True Power 750W Hybrid 
Case: NZXT Phantom Full Tower 
Monitor: BenQ XL2411T 144Hz 
  
Now all this cost me over £1000, but this is all overclocked and can run Crysis 3 Ultra at around 30-60FPS. 
Battlefield will run High to Maxed settings with an i5 and a HD 7850, in my opinion you are better off saving and spending a decent amount on a PC so it is future-proofed as games will come out in the future that you will wish to play considering that developers now are stepping up the game with new engines, i.e Unreal Engine 4 that will require some next gen hardware. 
Best place to look around, ask and get some good info would be Overclockers.co.uk and reddit.com. 
  
Also I found PCPartPicker.com helpful for selecting parts and getting a rough estimate on hardware prices. 
Sign up and post a thread on Overclockers.co.uk titled 'Help with new build', everyone will help and give you some complete setups!  
  
Tom    After all that I read the title, 'Updated Bought a Laptop'!