Stop
This is definitely a series that is better read one after the other--unless you have a really good memory for books.
I read book 2 around Christmas and had forgotten a lot of what had happened previously when I bought this a couple of hours ago and decided to read it straight away.
I remembered the east and west and the two members that ruled each side, that she had belonged to one but seen something that shocked/hurt her and she had run off to the other...and that was about it.
Sci-fi is not one of my favourite genres and because of that I think I'm going to end my reading of this series here at book 3.