Couple of ideas...
1- Try a computer fair, they often have these fans and other sort of things.
2- Remove the fan, and put ONE drop of very thin oil (not WD40) onto the bearing, dip a paperclip into the oil can, and use this to transfer the drop of oil. The oil I use is sewing machine oil, (3 in 1 is similar). The bearing is often to be found on the reverse of the fan underneath a sticker,