Heh didn't see the ring part of your question. Yeah noticed you got a Kirin Tor ring earlier, grats, they're pretty sweet.
And really, you're doing pretty well with those two. Upgrades possibly would include:
Signet of Manifested Pain: KT 25 man
--Stam/Int, SP, Crit, Haste. Basically the beefed up version of Spellshock + haste on it. Super nice ring, the only flaw is it doesn't have Spr

.
Seized Beauty/Lost Jewel: Random 5 or so bosses in 25 Naxx
--Both have Stam/Int, SP, and crit. Seized has direct MP5 (meh), while Lost Jewel has Spr. Spirit for the most part is superior by far over MP5 for priest, unless it has a LOT of MP5. Though 3.1 will be changing that dynamic to a certain extent, so who knows.
Band of Channeled Magic/Renewal of Life: Valor Badges (25)
--Both have Stam/Int/SP. Channeled has Spr and haste. Renewal has MP5 and crit. Both solid in their own way, depends on preference again.
Ring of Decaying Beauty: Random 5 or so bosses in 25 Naxx again
--Eh @ this ring. Stam/Int/SP, haste, MP5. Would only be a minor upgrade over your currents, if even.
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With those options, I'd go for KTs Ring to Replace Spellshock. And Lost Jewel/Seized Beauty/Channeled Magic/Renewal of Life to replace Loop of Kirin Tor, depending on what stats you want more--pretty much all good choices.
Not an incredibly big deal on the second ring, because Kirin Tor rings are being upgradeable for 1k gold in 3.1. I THINK they're being upgraded to item lvl 226 (though it might just be 213), so if that's correct it'd be KT 25 man/Malygos 25 man equivalent.