What to do about dangerous dog?

Almost 2 weeks ago ( Im gonna try to make this quick) basically there was an Akita in my backyard when I came home from school. It attacked my dog (he's okay now, just a few stitches). Basically it's (don't know it's gender) owner was looking for it and he must have been enjoying itself in my backyard because it also left a pile of $#@! in the middle of my lawn. I $#@!umed, like any logical person would, that she would stop walking down this route and avoid our house (since she only started walking this route recently). But no, apparently when I'm at school my brother has been seeing her walk down the block every day only like only a few days after the incident. I'm doing my homework, and my dog keeps whining. Then my brother calls me and tells he hears some one calling a name and walking around the neighborhood. I look out the window of his room and there she is, putting her leash on her dog. SHE LOST CONTROL OF HER DOG AGAIN (I know I sound like a hypocrite) and on top of that this is when I usually take Easton out. I could have easily run into the dog again and had to beat its brains out with a garden shovel. She's like a 5 year old with a dog, he walks her and is apparently an escape artist. What do I do at this point? Call animal control? I don't know where she lives sadly. I'm scared that her dog will revert the progress I've had with Easton, he's great with other dogs now and sometimes cats (only at the vet though).

What to do about dangerous dog?