Follies stage door
If worse comes to worse, you could always mail it to the theatre. A better idea would be to drop it off at the theatre yourself or somthing (like the LA STRADA poster, I would NOT loose that thing) that would guarentee its safe to not get lost in the mail. Things like ITW CD covers, she would be glad to sign and return in the mail. However, she does ask for a small donation to Broadway Barks (or Broadway Cares? I cant remember) for each thing you ask her to sign. Good luck!