I'm not trying to be a smart-a*** but if you cant even find it are you sure you can safely replace it??
If you really want to give it a go I suggest you buy a Haynes (or similar) workshop manual for your car.
This will give you all the info you need in words, pictures and diagrams to do this and many other repair and maintenance jobs on your car.
They cost about £20 from bookshops, Halfords etc. You will often find them in second hand bookshops, charity shops, online auctions and local press 'for sale' ads for £10 or less.
P.S., no, I dont work for Haynes!
digger, September 2009