Total: 162 pounds. It's a little bit more, but it'll be a lot faster and last a lot longer.
You may also want to consider getting a new HDD, as that's typically the part that makes a computer seem the slowest. If you decide to get a new one, find either a Samsung Spinpoint F3 500 GB or Seagate 7200.12 500 GB.
Looks pretty good admiral, amy i would recommend going with admirals suggestion, it may be 47 quid more, but the cpu is about on par with the intel one, except cheaper. but the ram is much faster, the motherboard is much newer too. and it appears to have ide slots for old dvd/hdd drives.
p.s maybe you can help me find a mobo admiral. ive already got a thread open, although im looking for a intel one, not amd.