Belt options:

-Hardened Elementium Girdle is a craftable blacksmithing piece providing dodge and mastery with a blue socket.
-Jumbotron Power Belt from Tron Council provides dodge and mastery with a yellow socket.
-If you are like me (cheap), you can go with the option from exalted Hyjal, the Belt of the Ferocious Wolf. Sure, it's a DPS belt, but you can reforge a good chunk of the crit to avoidance or hit. You should already have Hyjal rep from the cloak, so this is a good starter option.

Ring options:

-The Bile-O-Tron Nut drops from Chimaeron, providing dodge and expertise.
-Any Permafrost Signet from Conclave of Wind will provide a combination of dodge, parry, and mastery.
-Ring of the Battle Anthem, which has dodge and mastery, can be picked up with 1250 valor points.
-Rings seem to be a bit harder to upgrade than other pieces, so a couple of good starter 346s are the crafted Elementium Moebius Band which is one of the few ring options that provides a gem slot. It is not terribly expensive, if you can find a JC to make it (hint: I totally can if you are on Norgannon-US). Another good starting piece is Felsen's Ring of Resolve, for which any raid-prepping tank should qualify, as it requires Therazane revered status.