CSS hook per publication type?

We're creating a Drupal website with biblio functionality.

We have a few views containing biblio nodes of different publication types. One of these types, however, needs to be themed differently (ie. we have a separate "Talks" publication type whose nodes need to be given a different color from all the other types)

The problem is that there doesn't appear to be a CSS hook in biblio node views relating to the node's publication type.

What we did was add a few lines in the biblio/biblio_theme.inc file under theme_biblio_entry():

$type = "biblio-" . str_replace(" ", "-", strtolower($node->biblio_type_name)$_name));
$output  = "\n".'<div class="biblio-entry '.$type.'">' . "\n" ;

This works, but when the module is updated, the modifications obviously get lost.

How exactly would we go about making these changes permanent? Or is there another, better way to achieve the same thing?

Thanks for the help :)