Older puppy biting?

I adopted my approx. 5-month old female lab from the city pound five days ago. She bites constantly. I'm trying to be calm, have given her lots of toys and exercise, but she prefers my hands, arms, ankles, backside, face, etc. If I'd gotten her at a younger age, it would have been easier to teach her, but I know she'll figure it out eventually. I just need some advice because it's very painful, and time-out doesn't work, neither does saying "no" loudly--I'm at a loss. Please help!