Good fences make for good neighbors. It occurs to me that if you put barbed wire on top of the fence, and/or broken glass and build the wall out of cinder blocks, then you won't have to deal with them ever again. A bit expensive, but it should do the trick.
I personally would pour bleach over her lawn at this point if she has done everything you have said. Not that I am advocating you do anything illegal. You could also get a gun and wait for her to do it again. If she is on your property (even her arm) and threatening your animals you may have the right to defend your property, look up castle laws for your area.