You already have the total post, so in order to get the total post within the last week, it’s better if you do this on your functions.php
file:
function get_posts_count_from_last_week($post_type="post") {
global $wpdb;
$numposts = $wpdb->get_var(
$wpdb->prepare(
"SELECT COUNT(ID) ".
"FROM {$wpdb->posts} ".
"WHERE ".
"post_status="publish" ".
"AND post_type= %s ".
"AND post_date> %s",
$post_type, date('Y-m-d H:i:s', strtotime('-168 hours'))
)
);
return $numposts;
}
And then use it in the footer.
<?php echo get_posts_count_from_last_week(); ?>
To work with categories we could use WP_Query:
$args = array(
'cat' => 4,
'post_type' => 'videos'
);
$the_query = new WP_Query( $args );
echo $the_query->found_posts;