Well, first off, you shouldn't have level 60 gear. Period. It should only take you about 2 levels in Outland to replace all your Old-World gear. Or are you in level 60 OL gear already?
A link to your armory would be pretty helpful.
Secondly, do you have the Wrath of the Lich King expansion pack? If so, I would recommend heading off to Northrend now. 68 is generally regarded as the minimum for that content. The quest rewards over there are also pretty good, although nowhere near the Old World -> Burning Crusade gear jump.
If you do not have WotLK installed, then continue leveling in Outland to 70. I would look into finding groups to run Magister's Terrace, The Mechanar and Botanica in Tempest Keep (though those require flying mounts to access), Shadow Labyrinth, and the Black Morass in the Caverns of Time. But don't limit yourself to those only. If you can find a group for pretty much anything, I'd go.
I'd also recommend downloading the addon AtlasLoot Enhanced from
Curse and looking for fitting loot yourself. According to
this thread, a disc healer should look for these stats, in order of importance:
Spellpower > Crit >= Int > MP5 > Spirit > Haste > Stam
Good luck with whatever you do.