Perhaps, as someone suggested, she is an ENTP. The dominant intuition could explain her better.
Or she could be so far removed from reality that she doesn't even perceive criticism, which sometimes seems like it's the case based on the way she simply ignores people's criticisms of the Quibbler. In that case, I could see super-deluded INFP for her as well. It's just that she has none of that "quest for identity" thing going on...in fact, she has probably one of the strongest senses of self of any of the characters, in the face of all criticism and unpopularity. Also, she has no problem inserting herself unwanted into a group if that's what she desires, and this is something that I would think a sensitive INFP would rather die than do (to voluntarily be where they know they are unwanted? Ludicrous!). And I don't see her as warm at all...she was totally detached all the time, even in traumatic situations and in the face of death (Dobby's death, for instance).
Anyway, I can't believe I'm arguing over the personality of a pathetically underdeveloped character that appears in only 3 of the Harry Potter books. Lol.