When "ish" is added to a word in English it means "about, approximately, more or less".
If you are told to be at an office at eight sharp, you should arrive at 8:00, not a few minutes earlier or a few minutes later. Bit if you are asked to arrive eightish, you can arrive a little earlier or later. This is very commonly used for parties, invitations for dinner, etc/
So, I would say "sharpish" in the context of the librarians means "relatively soon".
I wish to add that the phase Vitor gives is PROBABLY from a headline of a newspaper or the title of a magazine article. The use of "sharpish" is certainly not common.
Merriam-Webster has a very complete but possibly confusing explanation.