its the cpu dual core? if not, you prob should buy it if it has a good case, pull the hdd, ram, video card out, and take the motherboard and cpu out and buy a motherboard thats takes latest cpu. and then invest in a quad core or for something cheaper dual core 2.5ghz.
is a cheap site. towers, motherboards, CPU's and etc. usually takes one day to send money to them and then as soon as they send the item it gets to your door by the next day.