Top comment from Argaloth's Page on wowhead. That's assuming the BH raid your in isn't taking 3 healers to be safe, in which case more dps is needed. If you think you can pull your weight on the boss then go ahead.edit: forgot to mention his enrage timer. Argaloth currently has a 5 minute enrage timer (300 seconds). he has 21,473,000 HP. this means you need 72,476 raidwide DPS on 10-man. assuming 6 DPS and 2 tanks (each half a DPS), this is 10,353 DPS per player. this should be easily achievable in 10-man with appropriate raidbuffs,
Edit: Just looked at your armoury and um... wow :S First thing I noticed was the obvious lack of hit like others said, and your reforges/gems ain't much better. Dont reforge haste > mastery. Mastery is yoru weakest stat. And those gems. I know your under hit cap (by alot) but dont ever gem 30 hit rating gems, especially when the socket bonus is useless to you (30 spirit? come on -.-).
Really, you should replace all those spirit items first. Spirit is useless to you now. Then see about getting some better trinkets. Seeing as your so far below the hit cap i'd suggest going to HoO (even normal HoO is good) and getting the hit trinket off the first boss.
Another suggestion would be to get Breeches Of Mended Nightmare. These are quite cheap now (on my server at least) and have almost perfect stats for you.
Again the reforging? One of your rings you are reforging haste > mastery. Dont reforge haste > mastery. SORT OUT THOSE REFORGINGS.
Ok im done. I can't do it anymore :< Here is a link to EJ's site. Read it and sort your mage out yourself. EJ Fire Mage guide
And OT. I personally wouldn't take you to a BH run myself.