As the the Quad Core, I suggest instead just either going for a high spec faster GHz Duo-Core (less cost for more performance - unless using a lot of multi-core enabled apps/games) or going for the latest, faster but more expensive i7 Core (if your motherboard can support it). There are very few games yet that make any real use of multiple cores and in those few cases still don't use it very well (Crysis is an awesome exception for this - multi-core and Nvidia support). Consoles don't have this threading and would require major coding overhaul to port FF14 to make use of more than two cores. Duo Core uses one for OS and one for App at all times at least. If you do get Quad, make sure it's 3GHz+ to make it worth it. i7 Core is different technology which removes a lot of bottleneck, but you might need a new motherboard, etc.
2GB Ram is rarely enough, it's survives but your'll notice a couple more gbs makes a performance difference, you should look into adding some more (4GB or 6GB should be good - make sure it's compatible with your old memory if mixing), specially if using Microsoft's 'memory hog' OS! Vista would gobble all that up and leave barely any for your game.
FF14 Min System Requirements are as follows:Operating SystemWindows® XP SP3
Windows® Vista(32-bit / 64-bit)SP2
Windows® 7(32-bit / 64-bit
CPUIntel® Core 2TM Duo (2.0 GHz)
AMD AthlonTM X2 (2.0 GHz)
RAM Windows® XP: 1.5 GB or higher
Windows® Vista / Windows® 7: 2 GB or higher
HDD/SSD SpaceInstalling: 15 GB or more
Downloading: Space on the hard drive where My Documents is located should be 6GB or more
Graphics Card512MB NVIDIA® GeForce® 9600 series or higher
512MB ATI RadeonTM HD 2900 Series or higher
Sound Card DirectSound® compatible sound card (DirectX® 9.0 or higher)
Internet ConnectionBroadband Internet connection or higher
Screen Resolution1280 x 720 or higher; 32-bit
DirectX DirectX® 9.0c
OthersMouse, Keyboard, Gamepad
As far as they go - graphic card is the only limit.
The GeForce GTX 480 is a sweet hardcore gaming graphic card, just make sure it fits, has two power cables,
very power hungry so make sure your power supply (PSU) is at least 550W+. Then your'll be lag free - high quality gaming in no time!
Happy gaming!