Mono,
Just get in your hands casting speed gear and recast helps as well,
which is a big + when you have specced on Wis and get that 8% faster recast.
No point switching to a druid when all the time the people that are topping the heal parses are the shamen.
You have to remember though you are a preventive healer,you goal is to keep the tank as high as possible, you do not have the spike healing that druids have so if the tank goes down to red your work becomes quite harder is all.
As malachani said, just pick up a couple of casting speed items and slowly by raiding and such you will upgrade em to something better.
Tso lego sets will help you as well for the beginning,especially with all the upgrades coming up with the next update,go farming for those shards and have the T2 set ready for it.
But as i always say, just relax sit back and have fun,it's only a game after all

The more you enjoy it the better you will be

Costas.