Unfortunately, getting your hands on one of those processors for a reasonable price is almost impossible. Try and explain the facts to your friends..friend...
The money he is going to spend will not be worth it unless you can get that chip for $10 including shipping.
The chip is not supported anymore (its an AMD chip by the way) the board is not supported anymore, the memory on the board is hard to find... can't get any clearer than that.
If a device is not supported, you don't want to invest anymore money into it. If the friend is having trouble with the PC and it has poor performance, you can kindly suggest an upgrade. You can get a barebone kit from Tiger Direct
for a very reasonable price and just use whatever components you can from his old box.
These are just suggestions but again, to be honest you won't find too much out there on unsupported, outdated hardware.