(you're saved in holy gear, so I'm going by your saved wow-heroes gear setup)
There is a tank belt in regular ToC 5 man, I'd recommend you go get that - it will make it much easier to reach 540 (or 535 like the previous poster stated). Reaching the defense minimum is your #1 priority as a tank.
I wouldn't aim for the hit cap - it's nice but not crucial. Expertise is a better threat stat until you hit 26 (which is pretty easy as a pally).
Brewfest trinkets aren't bad. You could get the Triumph armor trinket to replace it, but I wouldn't say it's your most crucial upgrade - I would get the tank helm next (the 245 one).
Your necklace is OK, but because you're struggling for defense I would suggest farming the seasonal boss in SFK for that one (it's identical to the 226 one from conquest badges iirc).
I would also enchant your cloak and shield with defense, should help a bit with reaching the defense minimum.
For some reason the armory won't let me look at your spec and glyphs, so I can't tell you if those are correct or not.
edit: do you know the rotation? if you don't know 96969, I'd recommend reading up about it on Maintankadin