Advanced Search by minimum/maximum values

A meta_query is an array of arrays. You only have an array.

    $query->set('meta_query', array(
        'key' => 'shru_price',
        'value' => $_GET['minPrice'],
        'compare' => '>=',
        'type' => 'NUMERIC'
    ));

It should be:

$query->set(
  'meta_query', 
  array(
    array(
      'key' => 'shru_price',
      'value' => $_GET['minPrice'],
      'compare' => '>=',
      'type' => 'NUMERIC'
    )
  )
);

And please validate/sanitize that user supplied data before using it !