.htaccess question

So, I am using a shared hosting account on hostgator and I'm trying to modify my htaccess files so that my addon domains don't get penalized for dupe content. I have one quick question. Do I add the following to the addon domain htaccess or do I replace the addon domain htacess with it.

Options +FollowSymlinks
RewriteEngine OnRewriteCond %{HTTP_HOST} ^addondomain\.co.uk [NC]
RewriteRule ^(.*) http://www.addondomain.co.uk/$1 [R=301,L]

RewriteCond %{HTTP_HOST} ^www.addondomain.the-hosting-domain\.co.uk
RewriteRule ^(.*)$ http://www.addondomain.co.uk/$1 [R=permanent,L]

RewriteCond %{HTTP_HOST} ^addondomain.the-hosting-domain\.co.uk
RewriteRule ^(.*)$ http://www.addondomain.co.uk/$1 [R=permanent,L]

Obviously that's just a template but my current htaccess file is


# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

So do I add the first inbetween the wordpress lines or within the ifmodule or do I just replace everything between the wordpress with the top lines of code or do I replace EVERYTHING. I'm not too familiar with this programming language so any help would be great.

Guess I'm not the only one not understanding your question. Please try us to tell us what you want to accomplish.