Now that you mentioned it, I think I simply used WoW-Armory to determine what upgrades were comparably easy to get.
Well, this is my personally gathered list, formed of stuff that are 1) rather easy to get (crafted, AH, Emblems of Heroism) and 2) good enough for all the raid dungeons.
HELMET:
[Helm of the Lightning Halls] - BoE Drop. Can be bought from AH usually for a reasonable price. Mostly easiest and the best resto helmet before Naxxramas.
SHOULDERS:
[Epaulets of Market Row] - BoE Drop. Can be bought from AH usually for a reasonable price. Mostly easiest and the best resto shoulders before Naxxramas. There's two alternative drops from HC Utgard Pinnacle (http://www.wowhead.com/?item=37398, gives crit instead of mp5) and HC Violet Hold (http://www.wowhead.com/?item=37875, gives haste instead of mp5).
NECK:
[Lattice Choker of Light] - Bought from
Dalaran for
25 Emblems of Heroism.BACK:
[Wispcloak] - Crafted by tailors. Costs usually quite a bit in the AH (I think I bought mine for around 500g). Materials: Bolt of Imbued Frostweave x 5, Eternal Life x 6, Eternal Water x 4, Siren's Tear, Frozen Orb.
HANDS:
[Lightning-Charged Gloves] - Drops from HC Halls of Stone (Maiden of Grief), 25-50% chance of dropping. The only other alternatives are purple Elemental gloves from the last boss of Ahn'Kahet: The Old Kingdom:
[Fiery Obelisk Handguards]WAIST:
[Beadwork Belt of Shamanic Vision] - Bought from
Dalaran for
40 Emblems of Heroism. Alternatively there's
[Mail Girdle of the Audient Earth] from Loken of HC Halls of Lightning and
[Slad'ran's Coiled Cord] from first boss of HC Gundrak. Both places are massive pain in the ass without really good group and gear, though.
LEGS:
[Kilt of Dark Mercy] - The Ebon Blade revered item. A slightly worse alternative is:
[Frozen Forest Kilt] from the Tree-Shaper in HC Nexus, 25-50% drop chance.
TRINKETS:
[Spark of Life] - From Sjonnir The Ironshaper at HC Halls of Stone. One of my most loved trinkets of all time.
[Soul Preserver] - From Mal'Ganis at Normal Culling of Stratholme.
[Je'Tze's Bell] - BoE World drop. Usually sold for insane prices, but if you can get it for a reasonable one, don't miss your chance.
[The Egg of Mortal Essence] - Bought from
Dalaran for
40 Emblems of Heroism. This is the choice you go for if you have those 40 emblems and haven't been able to get your hands on anything better already.
MAIN HAND:
[War Mace of Unrequited Love] - THE best resto healing weapon before raids with 25-50% chance of dropping from Keristrasza at HC Nexus.
SHIELD:
[Protective Barricade of the Light] - Bought from
Dalaran for
35 Emblems of Heroism. This shield is so awesome that you may have hard time deciding whether to even roll on the shields that drop on Naxxramas. Alternatively if you still lack the emblems, you can buy
[Zom's Crackling Bulwark] from AH if you can find it for a reasonable price.
TOTEM:
[Totem of Forest Growth] - Bought from
Dalaran for
15 Emblems of Heroism. There's no other contenders for this slot for PvE.
HC Utgarde Pinnacle and HC Violet Hold seem to have several rings with haste on them, and there's one in Azjol-Nerub that has crit instead. I was always pretty at loss with the rings myself, so I can't really help with those. Just keep in mind that when you find new rings and need to compare them to your old ones: haste, crit, spellpower, int and mp5 all take preference over spirit.
The rest of your gear is fine.
SUMMARY:
1) Start farming HC Nexus (main hand and legs) and HC Halls of Stone (trinket, hands), and other heroics for emblems. Stay clear of Gundrak and Halls of Lightning in heroic modes unless the rest of the team is top-notch and all dps are ranged. Culling of Stratholme is a bit bad choice as well since everybody usually wants to do the gauntlet that requires that you can run after the tank, never stopping to take mana breaks.
2) Do Vault of Archavon whenever possible. Normal and Heroic. The PvP stuff can offer alright upgrades, too.
3)
[Lattice Choker of Light] 25 EoH
[Totem of Forest Growth] 15 EoH
[Protective Barricade of the Light] 35 EoH
[Beadwork Belt of Shamanic Vision] 40 EoH
[The Egg of Mortal Essence] 40 EOH
Total: 155 Emblems of Heroism.
Buy them at whichever order you want to. I would personally claim that the trinket is your last concern at the moment, though.
TIPS:
Needless to say, mp5 should be your main priority at the moment (along with spellpower). Intelligence is important mostly due to Repleshnishment effect (along with granting both crit and spellpower). But if you find upgrades with mostly haste or crit on them instead, don't hesistate to take them. Mp5 is important, but not so important that you should have to sacrifice several other stats for it.
Recommended priority:
MP5 > INT > SP > HASTE > CRIT > STAThis recommendation becomes invalid once you no longer have issues with mana regen (e.g. in raids where you have insane mana regen buffs and will mostly be using Chain Heal). In such times, you can simply remove MP5 from the top of the list to the bottom. Having two sets of healing gear, one for mana regen and one for other stats, is not uncommon.
