This quest is not available in game.
For 45 Insignias of the Dawn and 45 Insignias of the Crusade you may choose an item from the Argent Dawn's treasure cache.
Greetings, friend. Have you insignias of the Dawn or the Crusade that you would like to redeem for items of great power?
I must warn you; epic purchases made at revered reputation with the Dawn are still quite expensive. I would advise that you gain a better reputation with the Dawn before moving forward with your plans.