What materials can I reference to find out more about her? I read The Hour of the Dragon and, after reading her chapter, I got an idea for an adventure.

but I was wondering if there was more about her I can reference (Otherwise I'll just have to make things up)
Well, just ignore this folks.

I just found a bit of info that's helpful here.

::Gotta remember to use the ol' search Function::
OK, new question, same person.

While, as with all games, the universe is yours to mess with as you see fit, I sometimes tend to be someone who likes to pay attention to details already written.

I do not yet have the book that gives details on Akivasha and am wondering what her personality is like. Might she be one to show someone the secrets to her immortality but conveniently forget to mention the downside to it (i.e. vampirism), just to see his reaction?

My first adventure I'm putting together involves the players discovering a vampire who became one due to Akivasha teaching him the spell 9For certain reasons).
I wouldn't know anything you didn't learn from Hour of the Dragon - but in case it's helpful at all, she has a write-up in The Road of Kings, if I recall.
She has a corrected write-up in Signs and Portents #21 and yet another revised version may appear in the upcoming Stygia sourcebook.