2-3 months?!? Are you talking about mail orders from the US or from within Japan? Because I live in a very remote part of China and can get stuff from the Chinese internet within a week... Japan in my eyes is much more modern and better organised, so that sounds almost unbelievable. Anyway, do you read Japanese? Because if you want to give it a try, I found an online Japanese craft store that seems to have all kind of things for quilting:
http://www.shugale.com
It seems that Amazon Japan also has some stuff (although probably more limited choices).
About your thimble problem: Although I'm doing hand-quilting myself, I'm really not the expert because I'm doing it all "wrong". So this might be a real stupid idea, but I was thinking you could try to use strong fabric band-aids or duct-tape to cover your finger?