Get more data from user profile

Hi and thanks for this cool plugin! It really did the job for what I wanted to accomplish 🙂
Hey, I was wondering if I could get more data from the users who login. Do you know how can I get this and populate it into my custom users’ fields?
Say I wanna get the user’s nationality or country of residence. Searching around I’ve found stuff like this:
$country = $signed_request["user"]["country"];
Would you be able shed some light on this?

Thanks again!

J

http://wordpress.org/plugins/facebookall/