Guess it is still there, but I have not seen it yet. Here is another book focusing on Goethe's collection of medals - no idea how expensive that is though:
http://www.medaillenkunst.de/publikationen/0000000312.htmThe museums from/about the "classical" period in Weimar are part of the "Klassik Stiftung Weimar". I briefly browsed their web site and came across these pages:
http://www.klassik-stiftung.de/einrichtung...nzsammlung.html(The grand-ducal coin collection, Residenzschloss, Burgplatz)
http://www.klassik-stiftung.de/einrichtung...sammlungen.html(Goethe's Collections - probably in the Goethehaus, Frauenplan)
In any case, the Klassik Stiftung should know.

Christian