How do you to treat a bad friend?

I, of course, have a friend of mine that does not care for me at all. Not for my feelings, thoughts, opinions, and advice. She will ignore me in group settings, unless we are both participating in a activity with the others. I will be spoken too only when the subject pertains to her. Honestly, I don't have much so I can't be used for anything. Though, probably my hot-spot is the most frequent thing she wants from me.

Now, I honestly would never allow someone to treat me terribly with this kind of mindset towards me. So, it is important for me to say I don't care that she could care less about me. I just am unsure of how to treat her. 

I don't dislike her or like her all that much. I am uncertain of how I feel. Every time I try to think of how I feel towards her I don't feel angry, sad, or even disappointed. It's like nothing at all. I should be bothered, I think.

Maybe I should give some background on the type of person she is. Self-centered, insecure, attention hungry, drama obsessed, and a copycat. She will make a conversation about her and if it isn't she won't participate. WILL interrupt with random noises, singing, playing music, etc. Got with a friends ex, dragged the issue out for 2 weeks. Broke up with him because he wore skinny jeans, wasn't actually interested in him, and liked another guy. Talks terribly about that ex after breaking up with him, he treated her kindly. Ignores her current one unless they are alone. At some point talked bad about all the friends she has ( not me, yet, maybe ). Purposely gets herself in trouble with things she was told not to do, and anyone with her. Will pretend to green-out, pretend to have an asthma attack, and almost got friends in trouble by doing that in class. Admitted to being a pathological liar. Much more.

How do I treat her?