$date = "2013-02-24";
 $week =  date('W',strtotime($date));
 $year =  date('o',strtotime($date));
 echo "First day of week". $From = date("Y-m-d",strtotime("{$year}-W{$week}-1")); 
 echo "end day of week". $to = date("Y-m-d",strtotime("{$year}-W{$week}-5"));