The Rizhiner (or Ruzhiner) hat is a normal shtreimel just with a high pointy hat crown (i.e. a pointy yarmulka).
Admor is a Hebrew akronym:
אדוננו מורנו ורבנו (adonénu, morénu ve-rabbénu), „our master, teacher and rabbi“.
About the shtreimel, refer as well to my post: