Loop Post Navigation Links – need category specific

I’ve a child theme, with a content.php file with post prev/next navigation code which works. I’ve installed a plugin for navigation loop (Loop Navigation Links by Scott Reilly) which also works.

I’m trying to get category specific code ($in_same_cat = true, ) placed correctly and I’m not a programmer. Thanks for your help!

Here is the code that works for all but the category specific:

<?php endif; ?><nav id=”nav-single”>
<h3 class=”assistive-text”><?php _e( ”, ” ); ?></h3>
<span class=”nav-previous”><?php previous_or_loop_post_link( ‘%link’, __( ‘ Previous |’, ” ) ); ?></span>
<span class=”nav-next”><?php next_or_loop_post_link( ‘%link’, __( ‘Next ‘, ” ) ); ?></span>
</nav><!– #nav-single –>

http://wordpress.org/extend/plugins/loop-post-navigation-links/