Here's the thing - it depends on how ethical the Seller is.
He doesn't HAVE to do anything.
Kudos to you that you're standing up and admitting your mistake.
However, if you showed me proof that your proxy was, in fact, $4,700 (remember, the seller never sees it), I would offer it first to the other bidder for $48. Because had your proxy been correct at $47, you would have immediately been outbid by HIS proxy which would have only upped the bid amount to $48.
Or, if the Seller is less ethical, he could try to sell it to the next bidder, but that would be unfair, because the 2nd bidder's bid of $69.99 is ONLY a result of your incorrect bid.
But, like other posters said above, it was your mistake, the "damage" isn't horrific, and the quilt has some value.
Lucky for you the other bidder didn't have a crazy bid in there as well. That's what we call nuclear bidding - and sometimes ends in disaster for at least one of the bidders. :wink: