Welcome to the board, specter!!!
Hmmm - well you have me a bit confused - you can do the library any time and it needs to be done before the ritual since things you need for the ritual are to be found in the library, so I'm not sure exact what area you are stuck in.
Check here:
http://www.volberding.com/WHints/index.html
Xignal has made an excellent walkthru including maps which should answer your questions!
Keep us posted!
Wyv