Yes, cross your fingers and try ILL. Not surprisingly, that book has a tendency to go "missing" from libraries so you may have to be on a waiting list for a while to get one of the rare remaining copies in circulation. (I had to wait a few months.) It will
be worth the wait, though -- there are definitely things in there that I haven't seen elsewhere. There are some omissions and notable biases, yes, but it's elevated status is not unfounded. I wouldn't pay hundreds of dollars for it, but if I came across a copy for under $100, I would seriously consider buying it. And I'm not one to throw money around.
I'm so glad you were able to get a publication date for the new edition. She's been promising it for a long time now.
BTW, if you're looking for a knitting reference, check out Montse Stanley's The Knitter's Handbook
if you haven't already. No book is perfect, but it's pretty comprehensive. (There are some things in Stanley that aren't in Hiatt so it's worth getting The Knitter's Handbook even if you do decide to shell out the dough for POK.)