Hi Janet
There's a chance you still may get something back ... or nothing at all

.
Although we would all like a quick response, this is not always the case. It is good that you have emailed the venue and they have replied that they do pass on mail - at the very least you know that your request has gotten to someone with John (e.g. manager) or to John himself.
Has John still got tour dates left to go? Some like to leave their fan mail until some time after they finish their tour before answering it, others like to do it as they go along.
So, it's really a matter of being patient (that's the hardest part) and hoping something does pop into your mailbox soon. However, like any other request you send out, don't be disappointed if nothing comes back for a long time ... if ever.
Good luck!! I hope you do get a reply
nowandagain [rockon]