Hey hey
I'm atm raiding as resto, so I've done the dungeon thing (norman and hc). My mana and regen will be a bit higher than you (110k with motw) but oc I've been there. I'll go through a few things, maybe it can help you.
While leveling when I got to 84 I thought Resto was in a really bad place. Mana usage was horrible. @ the start of 85 and some fights it was still pretty crap, but then I started to get some proper spirit gear and specially some spirit procing trinkets and things started to come right.
1stly things are very different now, unlike wotlk your tank (cooldowns, properly geared etc. ie avoidance > Stam) and also very importantly the dps needs to help you. There is no more standing in **** and finishing the cast before moving. With a crap group you will have mana problems.
My general rule is a DPS gets Omen of clarity procs, wg as a group and maybe a rejuv. If the need more than that, they fail and can die.
In my experience Cata encounters (dungeons and raids) works something like this (most of them anyway):
Tank dmg & some AOE group dmg
Then it gives you time to heal the group up in a cost effective way (wg, Efflo etc)
BUT during that time there are usually something that can kill a person or drain your mana IF you don't dispell, or dps screwsup
So its important not to panic and oc also to have a decent group as I said.
On to a spec. This is very important. I'd say variant of 8/2/31 ie
http://wowtal.com/#k=gsuame075.a8t.druid.MLi1D8 will work well for dungeons.
LB on tank, keep 3 stacks up either by using Nourish just before it expires if there is not much dmg or HT if there quite a bit of dmg. Or even another LB if you don't have time to cast the others, but keep it up as LB up gives you Replenishment (mana regen)
Swiftmend @ the right time with ppl positioned right.
I usually heal my dps'ers up with WG & SM with obviously the Efflo proc thing. I don't mind people going to say 30%, even the tank if I know the fight and know I have time to heal them up after the dmg. Rejuv if they really needs it.
It is VERY VERY important that you talent for Omen of Clarity and use it correctly. Its amazing how much it procs. Free casts = win when it saves you 5.5k mana. HT, Regrowth, SM is all free with it, so make 100% use of it!
Stats as a resto. Intel Int > Spirit > Haste > Crit > Mastery
All gear must have spirit on for you. Get Spirit proc trinkets. You can defo go full spirit as a start if you want. Tthat should help, but its not best as Resto in the end and I had no probs starting out right.
Haste, start by aiming for 7.15% (917 Haste rating) if you have the %5 haste buff (shammies, owls, sp's). (12.15% without it). Ye its more for raiding but its a good number to start aiming for and easy to get. You'll aim for higher numbers later (1221 Haste rating). Basically what that does is gives your rejuv a 5th tick of healing and also makes sure your WG gets an 11th tick (@ 5%)
Mastery is only really good for tank healing as we don't really have mana for keeping hots (rejuv mainly) on the others while we heal them. I currently reforge all my Mastery to Crit after I have my Haste soft cap.
Enchants and Gems helps massively! Even if you do some older cheap ones on your crap pieces.
I hope some of this will help you. Its all that I can think of now. You are welcome to pm me if you want to chat.
GL HF