so...where do i buy a really good Service Manual ??

hi guys,
I bought a service manual on cd rom from ebay for my 1999 S320.
it is absolutely worthless.
i went in it to find out how to replace the rear passenger side window regulator, no such thing in that manual.
i went in to find out how to change the oil and oil filter..., no such thing.
so, where can i get a real service manual for my car., on cd or otherwise ?
thanks,
Kevin Rea