This is a suggestion.
E4300 around 100
Asrock Dual VSTA 35 (OCUK DOES NOT STOCK THEM, so you will have to look on your own)
GPU 7600GT 80 or so
If the ram is DDR ram is here current PC, use that in the motherboard, it supports DDR1 and DDR2 ram.
Use the rest for her PSU/OS.
*EDIT*
Option 2
Asus bare bones 70
AM2 Dual Core 3800 64
1GB DDR2 GEIL 70
7600 GT 70
THen you need the OS. That is the best I can do. YOU couod get the GPU (like an x800XT or something) from MM, or auction.