I don't think that the people of 'New World' should know of Archangel, and that it's the highest ranking Angel. After all, according to Nigun or Sunlight Scripture, the highest ranking angel of all is Diminion Authority.
They don't and she didn't. Azazel told her he was an "Archangel of Sephira, one of the eleven most powerful angels in existence." With that one could infer that the other 10 are also Archangels, which is why she asks whether they come to assist.