How well would the game run on this computer?

[Saisya]

To give you a short and to the point answer, not well at mid or higher settings. At low settings, you're probably ok.

[Fwee]

if you play on pc the bigger the bestter you dont need 120hz unless playing cs or a shooter in professional grade and you dont even need it in the first place
get minimum a 26' with 16:10 support minimum 1920:1200
if you dont think your pc can run it

go to

it shows the scores for each part and shows how many people bought this or that...
this then shows the best pc to buy for your amount of money
you can sort at the top of each type by popularity or 3d score...
this is the best method for building pcs as its collected data from hardware specialists and the average consumer

http://community.futuremark.com/

however if on the ps3 the native 1080p is a resolution with 1080 at the end or whatevers closest

buy parts from ebay its always clearance price [$100-200.00 off each part]