To build on what poldaran said:
1.) Vitality to boots, the only enchant a holy paladin should ever use, except on your Shadow Resist gear set (which you won't need to BT/Hyjal).
2.) As far as trinkets I would actually recommend getting Xi'ri's gift from Sha'tar rep instead of the LCP, because...
3.) You want to change your chest. Yes I know thats some good stuff, but its not the stats you need/want right now. Save it for later or regem it for PvP. You seem to be a moderate PvPer anyway (prolly PvEing 60% PvPing 40%). I would reccomend the breastplate of many graces.
4.) You need to get the Sha'tar exalted mace and slap 81 healing on it. The healing you gain from that alone will make up for what you lose in your chest.
5.) You need to respec. Gruul you will be at max range so you will need Aura mastery. It is also the one fight in the game that if you're progressing on, Imp. Lay on Hands is crucial, it saves raids. You may actually have to have a PvP spec and a PvE spec, if you don't like having those talents in PvP. Many classes have 1 spec for raiding then respec when they're doing PvP. However, if you're that set on being with the big boys in 25 man raids, you need to change your spec around.
6.) Go ahead and finish out your gems. You have epic gear, don't put greens in them. The only two reasons to EVER EVER put a green gem in an epic piece of gear is if its an offspec you don't care about (ie. ret) or it holds you over until you get back to a major city and replace it with the good one. A little tip for you. Go through the list of possible gear drops for the content you're working on and go ahead and get the rare gems (even if raw) for those drops. Plan ahead. I'm sure you save enchanting mats ahead of time, go ahead and save gems.
7.) As a general rule of thumb stay away from spell damage and healing gear, unless you're replacing a green. You're not a shockadin, you're a healer. And actually if you get your healing up high enough you'll end up with more spell damage than a shockadin would have anyway!
8.) Make sure you load up on consumables. Whether you're going to flask or use elixirs, its your choice, but choose one and have plenty of them. Bring at least 30 super mana pots so you can use them without worrying about how many you have left. Go to Zangarmarsh and fish up some sporefish, its the best food buff in the game for paladins.