Billie Standish Was Here by Nancy Crocker
Okay I can't find the cover even though its on my desktop, so try to visualize feet.
Billie's an ugly, ignorant 11 year old with poor, mildly abusive parents, who has the misfortune of meeting a nice old lady and getting raped by her ne're-do-well son.
Lucky for Billie, the old lady's packin', and that night her son meets his maker with a gut full of hot lead. This lady not only takes out her progeny, she also takes little Billie under her wing and soon the girl isn't quite so ugly or hopeless, and her mom quits smacking her around. A boy even shows up in the picture. Of course, guardian angels like Miss Lydia can't stick around forever..
I liked the book, though it was some what predicable and tidy.. I'm just not sure if teens are going to be interested in a reading a story about a farm girl in 1964 dealing with rape on top of the usual "ugly, poor and without social prospects" issues. NAY