Обработка форм PHP, загрузка данных

<label>Producto</label>
<select name = "id_producto" class = "input_form" id = "idCategoriaProducto">
	<option value = "" selected = "selected">Seleccione...</option>
	<?php
	$q = mysql_query("SELECT id AS idProducto, titulo AS tituloProducto 
                      FROM productos WHERE operando = 1 
                      ORDER BY CAST(SUBSTRING_INDEX(titulo, '.', 1) AS UNSIGNED) ASC, 
                         CAST(SUBSTRING_INDEX(SUBSTRING_INDEX(titulo, '.', -2), '.', 1) AS UNSIGNED) ASC, 
                         CAST(SUBSTRING_INDEX(titulo, '.', -1) AS UNSIGNED) ASC");
	while($r = mysql_fetch_array($q)){
	   extract($r);
	   ?>
	   <option value = "<?= $idProducto; ?>" 
           <?php 
           if ($id_producto == $idProducto){ 
              echo"selected='selected'";
           } ?>
           ><?= $tituloProducto ?>
	       </option>
	   <?php
	}
	?>
</select>
<label>Criterio de Cobro</label>
	<select name = "tipo_cobro" class = "input_form" required = "required">
	<option value = "0" <?php if ($tipo_cobro == "0"){echo"selected='selected'";} ?>>Seleccione...</option>
	<option value = "1" <?php if ($tipo_cobro == "1"){echo"selected='selected'";} ?>>Fijo</option>
	<option value = "2" <?php if ($tipo_cobro == "2"){echo"selected='selected'";} ?>>Por Hora</option>
	<option value = "3" <?php if ($tipo_cobro == "3"){echo"selected='selected'";} ?>>Otro</option>
	</select>
	<div class = "clear10"></div>
<label>Monto</label>
	<input type = "text" name = "monto" class = "input_form" value = "<?= $monto; ?>" >
	<div class = "clear10"></div>