What a horrible, scary experience. OMFG. D:
Your injuries and that dog's death has absolutely nothing to do with you... he was unfortunate enough to be owned by an idiot, and he definitely should have been leashed, if not PTS long before he went after you. His owner abandoning him is proof enough that he was a badly bred, badly raised, badly owned dog. Try to think of it NOT as a breed issue, but as an owner issue. I don't avoid dogs based on their breed, but I do avoid dogs (especially when I'm out with mine) who are at the hands of morons (off-leash dogs... uncontrolled dogs... straining/lunging/staring dogs whose owners could care less... etc).
I don't blame you for being afraid. But, you know, plenty of people feel the same way about German Shepherds. You obviously know better than to judge that entire breed based on a few unfortunate GSDs who aren't given a fair chance to ever be good dogs. I hope you feel better soon, both physically and mentally. I can't imagine how freaked out I would feel if a dog ripped into me like that, regardless of breed.