I'm warning you now, some of the things I will say here will be harsh, but they need to be said.
1)Lose the healing shoulders. They embarass not only you, but the people you hang out with. If you haven't done it yet, the Cipher of Damnation questline has a pair of shoulders about halfway through that I consider better than anything pre-T4.
2)Look at your gems. Truly acceptable gems will have +hit or +dmg on them. Acceptable secondary stats when looking to meet a socket bonus: +Crit, Int, Stam, mp5. By secondary stats, I mean paired with one of the main stats. The best gems are either straight Hit, pure +dmg, or a mix of the two.
A couple things specific to watch out for:
i. The green gem in your helm is physical crit rating, not spell. You're not a melee mage, are you?
ii. Spell penetration is acceptable from two sources only, really. Cloak Enchant and Arcane Subtlety. I'm not sure why they put some on the T4 robe, but they did and it's not worth getting because of that. No matter how wonderful and pretty it is.
iii. Epic gear requires rare quality gems or better. If your gem's name is in green, replace it.
3)Gear from G'eras will be your main source of upgrades. If you do not have Spellfire or Spellstrike in a slot he has an upgrade for, then odds are you'd do well to get the item from him. First things I'd look to replace: Trinket, Cape, Wand. In that order. Get running for more badges.
4)Your rings will find good upgrades from running instances. From Spirit Shards, get the epic ring with the +dmg and the +hit. From CE Exalted, get Ashyen's Gift. They will serve you well.
5)As your one trinket gets replaced with the Icon of the Silver Crescent, consider going after either Shiffar's Nexus-Horn(Reg Arcatraz) or Quagmirran's Eye(Heroic SP). Or if you're willing to spend some major gold, Darkmoon Card: Crusade(Blessings Deck) is a very worthy upgrade. Only 2(maybe three) trinkets would I consider better than it. The first is the Skull of Gul'dan. The second is the Hex Shrunken Head. The one I'm iffy on is the Serpent Coil Braid.
6)A couple pieces of your gear lack enchantments. Even epic pieces. Under "Items..." on the left here is a subcategory called "Enchantments...". Research those.
7)After you've made most of these changes, see if your guild has a
Pattern: Boots of Blasting that they'd be willing to hook you up with. Craft those.
Now, you're really and truly raid ready for T5 content.