Add icon to collapse link

I want to add an icon to the collapse link. I am using Font Awesome. I figured out how to get it in there and look the way I want it, but obviously editing a plugin’s files directly is a bad idea.
I was wondering if there was a way to include some code in my child theme’s functions.php to add it, and keep it through plugin updates.

Here is the code in the plugin that I want to alter:

function bc_collapse($atts, $content = null) {
    extract(shortcode_atts(array(
    'id' => '',
    'title' => '',
	'open'=>'n'
    ), $atts));  

	if(empty($id))
		$id = 'accordian_item_'.rand(100,999);

	$output = '<div class="accordion-group">
        <div class="accordion-heading">
        <a class="accordion-toggle" data-toggle="collapse"
        data-parent="#accordion2" href="#'.$id.'">'.$title.' <i class="icon-collapse right bootstrap-collapse-icon"></i>
        </div>
         <div id="'.$id.'" class="accordion-body collapse '.($open == 'y' ? 'in' :'').'">
            <div class="accordion-inner">'.$content.'</div>
         </div>
        </div>';  

	return $output;
}

As you can see, I simply added <i class="icon-collapse right bootstrap-collapse-icon"></i> to the accordion-toggle link.
Here is an image of the result: http://i.imgur.com/UIV1YQl.png
Thanks,
Jake

http://wordpress.org/plugins/bootstrap-collapse/