Post per page code help needed

Hello!

Im trying to get 13 posts on my “index” page and 18 on my “older entries” (/page/2/) page. I think this is the code that controles this. What do i need to and to achieve that?

<?php if (is_paged()) $is_paged = true; ?>
		<?php $paged = (get_query_var('paged')) ? get_query_var('paged') : 1; query_posts("post_type=post&paged=$paged"); ?>
		<?php if (have_posts()) : $count = 0; $boxcount = 0;?>
        <?php while (have_posts()) : the_post(); $count++; ?>

            <?php if ($count == 1 && get_option('woo_home_featured') == "true" && !$is_paged) : ?>

Im super tankfull for any help! My php skills are not that good, but let me know if i need to provide any other code.