Hey all
Okay, I have a priest now (blood elf). My ultimate goal for WoW is to be a very good and reliable healer, but also be able to do some dps (long range, not melee) if that were ever needed in an emergency. I already have my priest, level 7, so I'm getting close to the point where I have to start allocating talent points
Basically I just want to know into which tree I should allocate the points first: Shadow, Disipline, or Holy? And how would I go about leveling it up? And then when I go dual-spec, which tree should I put my talent points into then?

Again, I mainly want to become an awesome healer with the ability to do dps when needed. I'm mainly looking at PvE (dungeons and raids), but might go into battlegrounds and two-on-two.
Thanks guys, all help is really appreciated