The easiest, cheapest and fastest way to get to/from the airport to the hotel is to take the Bay Area Rapid Transit (BART).
The cost is $8.25 for a one-way trip according to the BART Fare Calculator.
San Francisco International Airport (SFO) is in South SF and using BART will take under 30 minutes to arrive at Powell Street Station (899 Market Street, San Francisco, CA 94102), where you will get out and walk 3 blocks to the hotel.
