<human>: I appreciate any advice you can give me. My room mate has a friend that lives a ten minute walk from a bus stop that would take her to our university campus. She feels that such a walk is too long for her, therefore she drives her car to our house and parks there for the duration of her school day and takes our bus. She then comes back to our house at the end of the day on the bus and drives her car home. She doesn't ask permission, just comes over and parks, everyday. If this weren't rude enough, she invites herself over and does her homework and was she was even there one time when my other room mates weren't.

I confronted my room mates about this and they agreed that they were annoyed with her use of our house as a drop in centre. I asked if we could please talk to her about this issue, and they refused for fear of ruining their friendship. Today, I decided enough was enough and I'd put my foot down (this has been happening for a month) and wrote her a letter and stuck it in her windshield. It was very polite and said that we as room mates feel it is inappropriate that she abuse our home and that she may park on the day where she has a late lab, as a compromise. 

She, however, did not respect our wishes for her not to park her car in our spot anymore and in regard to my note wants to speak to us about still parking there! 

So, AskReddit, I need advice. Clearly this girl wasn't taught any manners and won't go down without a fight.

Can you condense the text into a few key points?
<bot>: room mates friend too lazy to walk to bus stop, parks at our house and takes our bus instead, refuses to stop despite telling her not to. What should I do?