Get the value from serialized custom fields

I’m trying to get the value from serialized custom fields
My _cp_showroom have this structure:

Array
(
    [home] => 1
    [cod] => 30408
    [tamanho] => 23
    [peso] => 0,25 Kg
    [attachment] => Array
        (
            [0] => Array
                (
                    [url] => /2011/05/Banana-Bag-Runner1.jpg
                    [cor] => 8
                )

            [1] => Array
                (
                    [url] => /2011/05/Banana-Bag-Runner2.jpg
                )

            [2] => Array
                (
                    [url] => /2011/05/Banana-Bag-Runner3.jpg
                )

        )

)

I’m trying this to get de ‘home’ key:

$args = array (
			   'cat' => 5,
			   'showposts' => 4,
			   'meta_key' => '_cp_showroom',
			   'meta_value' => array( 'home' => 1 ),
			   'meta_compare' => '='
			  );
$wp_query = new WP_Query( $args );

Can anyone help me?

Thank you…