From Vree, obviously. She is in Lost Bunker (Brotherhood), level 3 if I recall correctly (and wrong if I may guess), but she is in a computer room, dressed like any other BoS scribe.
I think there is an inteligence check on the right speech path... I think the first question is "What's behind the mutations"
I think about 7 or 8 and up on intelligence to get that disk. I remember. It took me that long to find out. Mentats and I think that surgery might help one to increase their intelligence to 7-8 and up to get the disk.