if(date('D')=='Sun'){ 
    $sw = strtotime('Sun this week'); //start week
    $ew = strtotime('Sat next week'); // end week  
    echo  date('d.m.Y',$sw)." - ".date('d.m.Y',$ew);
    }

if(date('D')=='Sat'){
    $sw = strtotime('Sun last week'); //start week
    $ew = strtotime('Sat this week'); // end week    
    }
    if(date('D')=='Sun'){ 
    $sw = strtotime('Sun this week'); //start week
    $ew = strtotime('Sat next week'); // end week  
    echo $ew;
    }
    if(date('D')!='Sat' AND date('D')!='Sun'){
    $sw = strtotime('Sun last week'); //start week
    $ew = strtotime('Sat this week'); // end week    
    }