After you've spoke to Raminus and told him about the Necromancer's he tells you to go get the staff enchanted with Delmar.
You say you're journal doesn't update? Is this with every quest...? Sounds pretty serious to me, worth exchanging your current copy for a new one. As for a way to get round the glitch, i doubt it but going straight to Delmar might work.
I would recommend exchanging your current copy of Oblivion for another copy at the place of purchase however. Your journal not updating is too serious a glitch to be able to play the game through with.