There's not much more you can do chicagoin.
Be there for her. Check.
Force her out of the house from time to time. Check.
Talk to her. Check.
You seem to be doing all that and more. The rest is up to her. The only thing I can tell you is to pound it into her head that she is not alone. Her story is like the story of many, many other girls. So many of us have to go through this deranged rishta process while dealing with all sorts of emotional, physical, and financial issues. And all along the way, there are people like Sara's ex friend, who we have to deal with. People who are "me me me me me" and MY pain and MY joy and MY life. You can't win with those people. Though she's upset now to lose her friend, trust me, she just got rid of a lot of dead weight that would only have ended up drowning her had she kept it. Right now, she's dealing in numbers...she seems to think that "I have one less friend so I'm that much more lonely." Once she realizes that the quality of her life has improved by not constantly worrying about walking on eggshells when she's around that girl, she'll realize that it's quality that matters, not quantity.
Don't feel bad. Don't give up on her.
You're a good friend.