I'm not sure if I should start this as a new topic or add on to the car buying thread.
My husband and I purchased a car 10 days or so after we arrived in San Juan. We took the advice offered here and used clasificadosonline and craigslist to find a used car. We also visited several car dealers and looked at their used cars. Eventually we chose an older SUV from a private seller. We made it a part of the deal that the owner go with us to transfer the title and to register the car. She agreed to go with us and I am SO GLAD we did it that way, it took 4 hours altogether and it would have taken us far longer if we had to do it on our own.
We have had pretty good luck getting some minor repairs done at Pep Boys, if anyone has other auto repair/parts dealers to recommend please do so!
Thanks to all -- this forum has made our move to PR much easier than it might have been.