Androgynous can be used both as expression and identity, although it would be more gramatically correct to use androgyne, a noun for identity. Genderqueer is a gender identity.
Agreed, androgynous/androgyny is a presentation, androgyne is a gender identity (the internal expression of androgyny - a mix of male and female). Genderqueer is a gender identity that I think of as "my gender is so far outside the box I can't find the box," though some people use genderqueer as a catch-all for being a non-binary gender. Added: Bi-gender is not the same as androgyne. Androgyne is a blend, a mix. Agender is a lack of gender. Neutrois is a gender, but not defined within the traditional male-female spectrum of gender. Bi-gender is having two distinct genders, either at the same time or switching back and forth. Genderfluid is similar to bi-gender, but involves more gender identities, which can include man/boy, woman/girl, androgyne, neutrois, agender, genderqueer, etc.
Great summary, Cailan. (For instance, I don't often hear people who aren't bi-gender explain what it is so well.)