Couple things:
1) yes you are at the point when should stop using the arcane tree to beef up your fire spells. 850-900 fire damage unbuffed (w/o mind mastery) is when empowered fireball starts paying off more, and will continue to increase faster as you get more dmg.
2) Get rid of that green trinket, use X'ri Gift from the sha'tar rep (your already revered with them). You may think that you need 26 hit rating, but reorganizing your gems will cap you and end up with more dmg.
3) Wrists and gloves need spell dmg and spell hit enchants respectively. Never enchant or gem for int, unless maybe you are 2pc T5 and need to maximize mana regen. The best gem you should look into is the one that drops in heroic Mech. It's the +5 s-hit, +6 s-dmg.
4) Also work on finishing getting exalted with SSO + aldor (the necklace is a much better raiding neck then the PvP one) and get exalted with CE for the nice spell hit ring.
5) Also keep in mind that badge loot is some of the best upgrades for you until SSC/TK. I had 1,106 +fire dmg and 32% crit without having a single piece of raid loot (10 man or 25 man).