After submit displaying results of a query on the same page

I have a form with fields like surname etc in it.
In my _validate function I search my db for clients with these details.
If none are found I display an error using form_set_error.
If clients are found I want to stay on the same page with the form fields populated as they were before submit was hit but also show the results of the search as a list below my search fields.

I have set $form['#redirect'] to FALSE and on submit my form field values remain as I want, but I have no idea of how to display my search results.

Can anyone help?

function client_search_form()
{    
    $form['search_firstname'] = array(
    '#type'  => 'textfield',
    '#size' => 25,
    '#attributes' => array('title' => t("Client's forename")),
  ); 
    $form['search_surname'] = array(
    '#type'  => 'textfield',
    '#size' => 25,
    '#attributes' => array('title' => t("Client's surname")),
  ); 
    $form['search_dob'] = array(
    '#type'  => 'textfield',
    '#size' => 14,
    '#attributes' => array('title' => t("Client's date of birth")),
  );  
  $townList = helper_get_locations();
    $form['search_town'] = array(
    '#type'  => 'select',
    '#options' => $townList,
    '#attributes' => array('title' => t("Client's town")),
  ); 
  $form['client_search'] = array(
    '#type'  => 'submit',
    '#value' => t('Search'),
  ); 
  $form['#redirect'] = FALSE;
  $resetHelp = t('Click here to clear your current selections');
  $form['client_clear'] = array(
        '#value' => '<input class="form-button" type="reset" value="Clear" />',
        '#attributes' => array('title' => $submitHelp),
      );

  return $form;
}

function client_search_form_validate($form, &$form_state)
{   
  $searchDetails = new stdClass();
  $searchDetails->firstname = $form_state['values']['search_firstname'];
  $searchDetails->surname = $form_state['values']['search_surname'];
  $searchDetails->dob = $form_state['values']['search_dob'];
  $searchDetails->town = $form_state['values']['search_town'];
  $clients = findClients($searchDetails);
  if ($clients == false)
  {
	form_set_error('', 'No clients found');  	
  }
}


// returns list of clients or false if none found
// $searchDetails is an object with following attributes:
// firstname, surname, dob, town
function findClients($searchDetails)
{	
	static $clients = null;
	if ($clients == null)
	{
		$clients = false;
		$first = $searchDetails->firstname; 	
		$surname = $searchDetails->surname;	
		$dob = $searchDetails->dob;	
		$town = $searchDetails->town;
	  	$sql = "SELECT md.nid, md.field_md_first_name_value as firstname, md.field_md_surname_value as surname, md.field_md_town_value as town, md.field_md_dob_value as dob
				FROM content_type_client_main_details md
				WHERE md.field_md_first_name_value like '%$first%'
				AND   md.field_md_surname_value like '%$surname%'
				AND   md.field_md_dob_value like '%$dob%'
				AND   md.field_md_town_value like '%$town%'
				ORDER BY md.field_md_surname_value;"; 
	  	$results = db_query($sql);
	  	if ($results)
	  	{
	  		$clients = array();
		  	while ($row = db_fetch_object($results))
		  	{
		  		$clients[] = $row;
		  	}
	  	}
	}
  	
  	return $clients;
}