loose heat sink

It looks as tho a heat sink has detached itself from my mother board.
I have a ASUS P5P800
In the middle of the board I found a heat sink hanging by two u-shaped gizmos off the mboard.
It looks like two more were missing, hence the hanging heatsink.
The area of the mb is the "Intel 82865PE Memory Controller Hub"

Questions:
Can I find two of these u-shaped mounting things and stick them in the MB and re-grease the heat sink and reinstall it?
Do I really need the heat sink installed?
The machine seems to be running fine.
How obsolete is this board?

TIA



Bob Heygood