Dragon Shaman Aura

[Rigdraf]

Im new to d&d and have just started a new campaign as a dragon shaman, i am also using the dragonborn template/race. I was wondering if the bonuses that the dragonblood sub-type gives to those who select draconic aura as a feat stack with the dragon shamans aura buffs they get as they level. If so can you point me towards the relevant info because my dm will not allow it unless i can prove it in writing.

[Khedrac]

Unfortunately I think the relevant text is where it says you can only project one aura at a time. The feat allows you the use of an extra aura, that has a different scaling rate (based on your dragonblood type), but it doesn't allow you to project more than one aura.
The feat (and your dragonblood type) will have no effect on the auras granted by your class.

[noce]

Dragon Magic, p. 86, says that a Dragon Shaman can learn auras presented there in place of his standard choices, and the aura he learns has the same bonus of other auras of his class and follows all the normal ruels for Dragon Shaman auras.

So:

you don't need the feat to learn Dragon Magic auras
those auras work like other auras of your class
you don't get double bonuses for both being a Dragon Shaman and having the Dragonblood subtype, only Dragon Shaman bonus applies

[Rangô]

Absolutly agree with noce, I'd suggest you to make a dip with Marshall class if you're interested in having more than one aura buffing your allies at the same time, you can find it in Miniatures handbook and also if you reach 12th level the double draconic aura feat.