Guild Wars 2

The desktop I am currently using now is old and is way overdue for a replacement. A friend of mine has suggested to just build a new desktop and that is what i plan to do. I have a rough draft of what I am thinking about putting in there and was wondering how well it would run the game. Any help is appreciated!

Processor: AMD FX-8320 Vishera 3.5GHz (4.0 Ghz Turbo) 8 core processor
RAM: 8GB
Graphics Card: Nvidia Geforce GT 630
OS: Probably Windows 8

I’m not to good with computers so bear with me haha. Is it possible to change the processor and if so would getting a new one improve the fps?

I knew since my computer is old that the performance would not be the best. But as of now I have been averaging 6 fps and about 2-3 fps in pvp and during large events. Is there anything I can do to improve this or am I out of luck.

OS: Windows XP Professional
Processor: Intel Pentium D CPU 3.20GHz (2CPUs)
RAM: 2gb
Graphics Card: Nvidia Geforce GT 630
Memory: >400Gb