My friend is impulsive and insensitive?

She takes me for granted and I know she talks about me behind my back. Everytime I talk to her, it's always about her and some boy that she likes. Whenever I try to say something, she always cuts in and says "kk cool. so anyways..." and goes on about herself. For instance, tonight she just told me about this boy she was trying to set her friend up with. She texted him and asked him out! She told me that he said he was dating this girl that he didnt really like, and then she texted back "Well, when your done with her, can we go out?" It's soo annoying!! Keep in mind, were not even teenagers yet. And when I asked her about this other boy she liked, she said "Well, *the first boy she asked out's name* isn't going to break up with his girlfriend for a month, so I've got plenty of time for him!" When I tried to talk to her about it, she said "lemme guess. your gonna say that i'm not very nice, huh?" Also, she only talks to me when she has gossip or needs advice. Whenever I ask her for advice, she says "aww poor you" and goes on about her. I'm so sick of it!! I don't generally get annoyed about this kind of stuff, but it's been building up for a year!! She used to be super nice and funny, and I don't want our friendship to end. How do I talk to her?!