Write her a letter to her with your contact info, and ask for her to contact you regarding the matter. Mention that if she doesn't contact you in thirty days(plenty of time to resolve this dispute, let alone just contacting you to start discussing the matter), you'll be taking the matter to a higher level. Send a copy of the letter to your landlord. Send three letters, once every week, and after the third week wait a week then write a letter stating that youve exhausted all measures.
Explain how and why the noise disrupts you. Don't just say "it's too loud", say "I'm trying to study at 8pm and the noise is distracting." Come up with a solution, maybe for times when it would be ok for her to play the music, etc. Ask if you can come up and suggest a reasonable volume that would be ok for both of you. Who knows, maybe she's deaf and doesn't know? Communication is key here.
Even better, make some brownies, pie, or a cake or something, and bring it up, and mention how you would like to get along. She sounds like she may be socially retarded and may just need a little nudge in the right direction. Getting along doesn't mean you have to hang out, it just means you can be pleasant to each other and respect each other's space. Who knows, maybe there's something you do that annoys her, and that's why she doesn't want to have anything to do with you?
What's the old saying? Honey attracts more flies than vinegar. Be nice to her and she'll be more willing to comply.