Despite an increasingly uncertain economy, thousands of homebuyers around San Francisco Bay kept snatching up foreclosed homes last month, dragging down the median home price by 41 percent from a year ago, a real estate tracking firm said Thursday. The median home price in the nine-county region plunged to $ 375,000 in October, compared with $ 631,000 in the year-ago period, according to San Diego-based MDA DataQuick.