previous & next posts with category name

i have a query – in the beta of the theme i have (v2,beta 4) there is a little change i would like to make to the “previous post” and “next post” section on the sidebars.

instead of saying “Previous Entry”, i want it to say “Previous (category title)” and “Next Category title”)

at the moment i have it sort of working:

<?php if ( is_single() ) { ?>
<li>
	<ul class="sb-tools"><?php
			$category = get_the_category();
			$cat_name = $category[0]->cat_name;
			previous_post_link('<li class="previous-post">%link</li>', 'Previously in '.$cat_name, TRUE, '102'); ?>
			<?php next_post_link('<li class="next-post">%link</li>','Next in '.$cat_name,TRUE, '102') ?>	</ul>
</li>
<?php } ?>

i dont know enough about php to know where to put the span etc. any pointers would be appreciated.

ideally it would end up in the format:
“NEXT IN (CATEGORY)
name of post” etc.

thanks in advance.