On your rig. Stick with the 920, it's still more than enough to rip through most games. Overclock it to roughly 3.6 -4ghz. It should take it if it's d0 stepping. Add 3 new sticks of ram, 24gb can be bought now for ~120 USD and it would take advantage of triple channel.
On hers, I'd upgrade the Motherboard and cpu, to an i5 3570k which can be done for roughly 400~ at a store like microcenter. You can buy an i5 for roughly 160 dollars and a motherboard for 200. If you buy them together you save 40 dollars