I remember someone said that it was possible to upgrade toe Mace of disruption to +2, but how do you do that? I haven't found out how yet and other than one post I read didn't even know it was possible. Can't stand that this killer of undead weapon is only a +1. Any help is appreciated.

You need illithium to upgrade the mace. Take the mace and the pure illithium to Cromwell.
Do you need a spoil as to where you get illithium?

There's only one way, so if you've already given it to a certain sculptor you're going to have to settle for the unimproved mace.

Minor SPOIL ahead....

To begin a quest with which you can upgrade the Mace, you need to have completed the Unseeing Eye quest. After this is done, speak to one of the clerics in the Temple of Helm. He'll start you on the aforementioned "scultpor's" quest. I'll leave the rest for you to discover.

Ahh yes, forgot all about the illitium quest. Forgot to talk to that priest after doing the quest. No spoiler needed, thx guys.