Looks like you're still carrying a couple of level 85 trinkets, which you should have replaced with green items while levelling in Pandaria (you can buy 408 ilvl ones from a vendor as a bare minimum!). Also you have the wrong gem in your helmet, should be a burning primal diamond (intellect + 3% extra crit damage I think).
As you're a frost mage, you should stack and reforge to 15% hit cap, then go for haste, mastery then crit on your gear as of 5.4 patch.
Another tip for quick gear is do battlegrounds for honor, and buy the whole honor set to fill in your gaps including weapon, or run dungeons and convert your justice points into honor for the same reason. PVP gear has exactly the same stat distribution as PVE gear of the same level, so nothing wrong with using it to do dungeons or LFR.