You can use that code in any template you like – for example in sidebars or before/after main content. You just need to avoid using the shortcode in the main loop: everything else is up to you.
Let’s say you have a template like this:
<div id="content">
[your main loop]
</div>
<div id="sidebar">
[sidebar code]
</div>
You can use the shortcode above everything like that:
<?php do_shortcode('[showsingle ...]'); ?>
<div id="content">
[your main loop]
</div>
<div id="sidebar">
[sidebar code]
</div>
This will also work for the Category->Page binding, only if in the category.php files:
<?php do_shortcode('[showauto]'); ?>
<div id="content">
[your main loop]
</div>
<div id="sidebar">
[sidebar code]
</div>
Otherwise you can use it in your sidebar, maybe using the [showlist] shortcode:
<div id="content">
[your main loop]
</div>
<div id="sidebar">
<?php do_shortcode('[showlist ...]'); ?>
[sidebar code]
</div>
Hope it helps!