How to use full length of the upper part of the content and below of it is a content with a sidebar?

All you need to do is wrap the additional content in a conditional so that it only shows up where you need it to. You probably want either is_home() (for the Blog Posts Index) or is_front_page() (for the Site Front Page), like this:

<?php
if (is_home()) {
  // your addition content
} ?>
<article id="post-<?php the_ID(); ?>" <?php post_class(); ?>>