User segmentation on Facebook

I run a Facebook application and I want to get information about my users who are logged in with Facebook so that I can post their messages based on their demographic groups.

I want to segment them based on information such as their age group, country, gender, language, and any other such things. How can i do this? I tried to look at the personal information that the Facebook API provides, but I could only see the age range and it said above 21 for a 28 year old user without any upper limit, which is completely useless.