If you need a block of rooms, I highly suggest calling the Comfort Inn Hayward and asking for Kanti, who handles such matters. I have worked with motel managers on a number of events and this gentleman wins for patience, charm and plain-dealing. After my office manager (misguidedly) cancelled part of our group reservation, he calmly changed the booking back with nary a snide remark when I called him later.
The Executive Inn in Hayward is a slighly more upscale venue with real conference capabilities. Prices for guest rooms seem to hover around $120 per night. The Executive will, however, require you to physically host your nightly reception and all alcohol must be surrendered at midnight.
If you need the beds but not a meeting room, take Comfort Inn. Then, if you want to throw money around, take the BART into San Francisco.