I know that it exists, because gegnir.is gives the following bibliographical information:
Höfundur Arnaldur Indriðason 1961
Titill Vetrarborgin [hljóðbók] / Arnaldur Indriðason ; Guðmundur Jónas Haraldsson les.
Staður Forlag Ár [Kópavogur] : Orð í eyra, 2006.
Lýsing 1 geisladiskur (MP3) (10 klst. 35 mín.).
I just can't find any online shop which sells it. Any advice would be greatly appreciated
Writing poetry in: Scottish Gaelic, German, English.
Reading poetry in: Latin, Old Irish, French, Ancient Greek, Old Norse.
Talking to people in the shop in: Lithuanian, Norwegian, Irish Gaelic, Saami.
Listening to people talking in the shop in: Icelandic, Greenlandic, Finnish.