Spoiler -
The Eye of Vecna can be found as random loot dropped by a greater glabrezu in Undersigil after you return from Carceri, but I have never even found the greater glabrezu...:/
So, you could go here
http://www.bootstrike.com/Torment/hints.html (scroll down) and download the Tome 'o Cheats, that can give you the Eye of Vecna, except I think you have to start a new game.
Spoiler again -
As for the spell Ignus Fury, I can't remember the exact way to get it...but if you download the above Tome o' Cheats, I'm fairly sure that you can get the spell..but I'm not too sure.
Hope that helps.