Before we get on topic...no where near Druid? We blow Druids and Shamans out of the water (which is getting some attention in the next patch) and we are on par with Holy Priests in most fights (we surpass them in some and they surpass us in others, but it's usually close). Paladins, they are another story, but even I can beat them sometimes or at least ride their coat tails for the entire fight. Priests, both specs, are in a very nice position right now and with the Discipline buffs coming down the pipe soon, things are only getting better.
Now more on topic...
You can't really expect much DPS from a healing spec. It's not realistic or reasonable for your guild officers to ask this of you.
The best you can do is have 2/2 Train of Thought, Holy Fire > Smite while DoT is up > Penance on CD. Do that while never letting your DoTs drop off for long.
Now, if you plan to stick with this you need to spec like this - http://www.wowhead.com/talent#bfGR0RsbcRbo0hZG00b