Intel Core 2 Quad Q9300 2.5GHz 45nm, is another option for a similar premade. As for the RAM, I read that XP does not fully utilize more than 2-3 Gb of RAM, does this mean I will also have to acquire a new operating system or is this a given since I have a Quad core processor? (I only have the lightest grasp of these topics).

I would give it a go, but I want to do some research before tackling the biggest hump, buying the expensive computer