I ran into a similiar situation, my wife is 5-0. She had a 44cm panasonic sport (hi-ten). I gave up on finding a better frame and just improved the parts. Bottom line is that fit far outweighs anything else - especially as a casual ride. You may end up settling on a frame - I've rarely seen 42cm-44cm frames at a reasonable amount - but they are out there (so I've heard). Early on, I was close to getting a 3 reshno - should have pulled the trigger.
What's interesting is that I bought a raleigh marathon (youth version) for my 10 year-old for a litle over $100. It's also a 44 cm frame, but like the above bridgestone, the rear wheel is 27" and the front is 24'. I mention this because the above bridgestone is likely a youth bike.
Good luck with the search. Asking around, like you're doing, is probably the best option. Worst case, check out philly CR for small, lower end frames - build it up and keep your eyes open for a better frame option down the road. I bought the marathon from the guy on CR with tons of beater bikes in his garage (outside Philly/Havertown - this guy
http://philadelphia.craigslist.org/bik/1820174670.html ). It's likely he has a 44cm beater. He is a nice guy.