I know the feeling Julia! When members here from the U.S, certain parts of Australia and The UK started getting their tickets, I was honestly really starting to get worried, even though the official website said that NZ was one of the countries where the screening of Led Zeppelin: Celebration Day was going to take place.
From the 13th, I literally drove myself insane by constantly checking websites such as eventcinemas.co.nz and Hoyts.co.nz to see if there was any news. I even took the plunge to email Customer services at Event Cinemas to ask them about the screening and on the same day I found the ad on hoyts.co.nz, the folks at Events Cinema emailed me to let me know that the movie was going to be screened on the 18th of October at select regions in Auckland and Wellington and that more info was going to follow soon on their website.
Like you, I haven't got my tickets yet and well, everyday I make it a point to check those websites. I really fear that if I don't, I will be missing out on a lifetime opportunity! Anyway, I am taking an educated guess here and I assume that tickets will probably go on sale on the 1st of October in NZ but I have to alert you to let you know that tickets are officially on sale in Italy! Go buy them ASAP!! I think this should make you very happy!