I just sold a copy less than a month ago for $2250. Had a few bidders, too. I sold because i just don't think it's going to go higher. I still have a personal copy that I'll keep, but a 9.8 should still be able to fetch 2K if you do a legit auction timed right.
Mine ended about a week before the season premiere for about the same. The seem to be going for 2k +/- a few hundred. I never thought this book would ever reach this amount, so I guess I would be surprised if it ever got higher. But on the same token, the book is as popular as ever and the show just announced a spin off . . . I don't know if I see the book dropping to 1500 on a consistent basis.
However, the price is heavily dependent on the show. If the show slows down, or if this season sucks, then maybe we'll see a drop. But season two sucked pretty hard until the end, so who knows. A season or two more will be enough for syndication and when that happens...