$weekday = date('w',strtotime($date));

$weekday = $weekday == 0 ? 7 : $weekday;

$fr_week = 1 - $weekday;

$to_week = 7 - $weekday;

$fr_date = wz_get_addday($date, $fr_week); // 월

$to_date = wz_get_addday($date, $to_week); // 일

// 날짜구하기

function wz_get_addday($day, $add) {

    $day    = preg_replace('/[^0-9]/', '', $day);

    $y      = substr( $day, 0, 4 );

    $m      = substr( $day, 4, 2 );

    $d      = (int)substr( $day, 6, 2 );

    if ($add >= 0) { 

        return date("Y-m-d", mktime(0,0,0, $m, ($d+$add), $y));    

    }

    else {

        if ($d > $add) { 

            return date("Y-m-d", mktime(0,0,0, $m, ($d+$add), $y));

        } 

        else {

            return date("Y-m-d", mktime(0,0,0, $m, ($d-$add), $y));

        }

    }  

}