It looks like Bayview 2br units are around $2700/mo (as of February of this year). Based on this, I'd guess a 3br is going to run you around $3500/mo.
The exact price of a specific unit is going to vary a lot depending on the specific location (home values can vary from block to block in SF), the size of the home, amenities, and finishes.
If you'd like help looking for a rental, or marketing a house to rent, I'd be happy to help.
Great question. There are some great sites that will give you the approximate rental prices like Rentometer.com and Ziply.com.
Rentometer and Ziply.com even gives you the statistics on the bottom 25% of rents and the highest rentals received in that area. I personally use these sites to gauge if the rent of my income property is still within market value.
If you are considering renting out your home and need assistance with the property management, I would be happy to help answer some questions you may have.