What to expect, prepare, bring to a short-noticed meeting solicited by a University Press editor?
It is unlikely that any editor is going to make any commitment to you about publishing your work, other than a book idea. You should come to the meeting with the same attitude. Don't make commitments or sounds that seem like commitments. Take a draft of your work (or an abstract) and be prepared to (a) listen and (b) sound interested. 

Get and give business cards.