sounds like she's had a really tough time..
Okay, well... a few things that I would personally do is...
Take her places where there are fewer/no people.
(since I have a back yard) try and set up a newspaper in the yard and leave her tied there (reasonable length!) for a little while and watch from somewhere where she can't see me, if she goes on the paper outside I'd come outside, praise her gently (not sure how she'd react to active praising), and slip her a treat.
Shorter walks and more frequent, so she becomes accustomed to coming home before she becomes accustomed to going out.
Give her 5 minutes alone time couple times throughout the day.. (just pop outside for a couple minutes, come back in) and if she "goes" while I'm out, then show her as I take the paper outside, and Then praise her.
Introduce her to new people, one person at a time, nice and slowly, to show her that not everyone she meets is a threat.
Get her to know that everyone you greet with a handshake or a happy conversation is safe/fun.
The more of your people she's okay with, the less "strangers" would be an issue.
uhm... yeah.. that's the first things that come to mind.