Did you agree to quilt it for her? If not, just tell her that you will not be able to do it. Period. If there are other LA quilters in the area tell here how to get in touch with some and let it go at that. Chock your lost time, fabric, etc up to experience. The 'friend' needs her own experiences and then she might value what you've already done for her. Three deep breaths and make the call right away so she won't be able to say you didn't give her enough time to get it done elsewhere!
Believe me, you'll feel lots better when you do! Life it too short to agonize over this!