Oblivion shivering isles help?

i dont have the Attenuator of Judgment anymore in my invintory so i got to the end of the dungen and now i cant do anything (btw this is for the a Better Mouse Trap quest) i dont know how i got rid of it because you cant drop quest items also i started this quest when i first got the game (a long time ago) and just now tryng to finish it all besause i just finiseh almost all of the quest lines. and if you finish the main quest line is there anyway to get sigiel stones.