Good luck!
For future reference you might be interested in
www.flysfo.com which gives a lot of info. Sadly there is, in fact, a 50% surcharge for taxi fares 15 miles or more from sfo, as well as a $2 surcharge (I guess for leaving the airport
). I was quite shocked at the taxi fare the one time I had to take one to my home due to a delayed flight and no shuttles.