How do I pasa a url parameter to wp_list_categories

I want to pass a URL parameter to wp_list_categories so when my sub-cagtegories are displayed and then clicked by a user, they are taken to a page where the posts are sorted by the highest rated post first.

I need to append this to each subcategory link:
?r_sortby=highest_rated&r_orderby=desc

my code looks like this:

<?php if (is_category(‘illinois-bars’)) { ?>

<?php if (is_category()) {
$this_category = get_category($cat);
if (get_category_children($this_category->cat_ID) != “”) {
echo “<h1>Subcategories</h1>”;
echo ”

“;
wp_list_categories(‘orderby=id&show_count=0&title_li=
&use_desc_for_title=1&child_of=’.$this_category->cat_ID );
echo “

“;
}
} ?>

In plain english this is what happens.

is the category ‘illinois-bars’ ?
If it is
then display all the subcategoris for the category ‘illinois-bars’
which results in links that look like this:
sub-cat 1
sub-cat 2
sub-cat 3 …and so on

I want this to happen

is the category ‘illinois-bars’ ?
If it is
then display all the subcategoris for the category ‘illinois-bars’
which results in links that look like this:
sub-cat 1?r_sortby=highest_rated&r_orderby=desc
sub-cat 2?r_sortby=highest_rated&r_orderby=desc
sub-cat 3?r_sortby=highest_rated&r_orderby=desc
…and so on