How to customize the sidebar for pages and categories?

Please look at my site here. Also, please realize I am not a really good coder, I just copy and paste a lot, and try to see how things work and then change them.

For the top-menu, I used the following code:

<ul id="menu">
<li><a href="<?php bloginfo('url'); ?>">Home</a></li>
<li><a href="<?php echo get_category_link($blog_category_page); ?>">Blog</a></li>
<?php wp_list_pages('title_li=&amp;depth=1' ); ?>

</ul>

This should make a ‘home’ link, links for all parent pages and a link for one category, which is my blogpage. To make this work, I also added a config.php with the following code, because my blog is category 1:

<?php

// blog category page
$blog_category_page = 1; // category id

?>

This is all good, and exactly how I want my site to work. I want some pages, and one blogsection. Now come the problem: I also have a sidebar that appears everywhere, on the pages and on the blogcategory. I have the following code on sidebar.php:

<ul><?php
  if($post->post_parent){
    $parent=get_post($post->post_parent);
    $children = '<li><a href="'.get_permalink($post->post_parent).'">'.$parent->post_title.'</a></li>';
    $children .= wp_list_pages("title_li=&amp;child_of=".$post->post_parent."&amp;echo=0");
  }else{
    $children = '<li><a href="'.get_permalink($post).'">'.$post->post_title.'</a></li>';
    $children .= wp_list_pages("title_li=&amp;child_of=".$post->ID."&amp;echo=0");
  }
echo $children; ?>
</ul>

this makes the parent page appear in a menu, including all child pages. So far, everything is OK! But I also have the following code in the sidebar.php:

<h2>Categories</h2>

			<ul>
				<?php wp_list_cats('sort_column=name&amp;optioncount=0'); ?>

			</ul>

		</div>

		<div style="margin-bottom:10px;">
			<h2>Archives</h2>

			<ul>

				<?php get_archives(); ?>

			</ul>

This shows the archive and the categories. This is no problem on the blogcategory (clicking blog in the topmenu), since they belong there, but on the other pages, I do not want this to appear. How can I do this?

So, to sum up: I have one category ‘blog’, and some parent pages in my menu. On the pages, I do not want the archive and category links in the sidebar. On the blog, they are fine. Can I exclude these pages somehow?

If anyone needs more info, just ask. If someone is available to help, I can always send some files.