Use of WP_Query

This might have a very simple solution, but I’m really struggling. I’m looking to pull sub-pages and their properties: a thumbnail, the excerpt etc. — things that I can’t get from simply listing the pages.

I’ve used a WP_Query to call this information; and this works well. My issue is with subsequent page processing. Simple requests (like get_author() ) don’t seem to work correctly.

Key question: how can I return the processing to the original page, rather than processing my WP_Query?

My code is here for the thumbnails…

<!-- THUMBNAILS -->

<?php
       $marberCurrentPage = $post->ID;
       $marberSubPages = new WP_Query();
       $marberSubPages->query("post_status='publish'&post_type=page&orderby=menu_order&post_parent=" . $marberCurrentPage);
       while($marberSubPages->have_posts()) : $marberSubPages->the_post();
?>  

	<div class="sub-page span-12 last">
		<div class="sub-page-thumb span-4"><a href="<?php the_permalink(); ?>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><img src="<?php bloginfo('template_directory'); ?>/scripts/timthumb.php?src=<?php bloginfo('url'); ?><?php echo get_post_meta($post->ID, "thumb", $single = true); ?>&amp;h=162&amp;w=220&amp;zc=1" alt="<?php the_title(); ?>" width="220" height="162" /></a></div><!-- .sub-page-thumb -->
		<div class="sub-page-text span-8 last"><h4><?php the_title(); ?></h4><?php the_excerpt(); ?>
</div><!-- .sub-page-text -->
	</div>

<?php endwhile; ?>

<?php rewind_posts(); ?>

<!-- THUMBNAILS end  -->

…and you can see the page itself here…

https://uktheme.co.uk/wp263/phasellus/

…you can see that the author appears twice on the page (on the right sidebar as ‘admin’; and under the body as ‘Tester’). Tester is correct (and appears before the WP_Query above), admin is incorrect.