How do i change the PHP file so the filters are in a specific order

I have my site set up https://cjsukimport.com/?page_id=24 and I need to change the PHP file so that the filters are in a different order than they are now. Does anyone know how to do this?

The current PHP code is:

<p class="portfolio-filters" id="portfolio-filter">
					<span>Filters:</span>					

					<a class="button" href="#all">All</a>

					<!-- Grab just the category slugs and list them using our markup -->
					<?php 

					if(get_post_custom_values('category_filter')) :     // If the category filter exists on this page...

					$cats = get_post_custom_values('category_filter'); 	// Returns an array of cat-slugs from the custom field.

					foreach ( $cats as $cat ) {
						$catsluglink = '<a class="button" href="#'.$cat.'">'.$cat.'</a> ';  // Create a link using our markup now
						$acats[] = $catsluglink; 								// Turn the list of ID's into an ARRAY, $acats[]
					}			

					$cat_string = join(' ', $acats);					// Join the ARRAY into a space-separated STRING
					echo $cat_string;
					endif;							

					?>

				</p>