Can I use BA/American Airlines air miles on another carrier?

The question I have is that my BA frequent flier account expires Nov. 8. We have a family trip we'd like to take to Florida in October. BA obviously doesn't do domestic travel. There are no flights available on BA's partner, American Airlines, on the dates we are traveling. Can I use these miles on a carrier who isn't a partner? Can I sell them for cash to buy tickets on another airline? I can't renew my BA membership because I am no longer flying with them but I hate to lose the air miles that I have aculated. Any suggestions?