Do you know what server your website is on?
If a Unix / Linux server runnign Apache there is some simple code to put in a .htaccess file in the root folder that will sort out your problems:
Code:
Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_HOST} ^(www\.)?domainname1\.com [NC]
RewriteRule ^(.*)$ http://www.domainname2.com/$1 [L,R=301]
RewriteCond %{HTTP_HOST} ^domainname1\.com [NC]
RewriteRule ^(.*)$ http://www.domainname2.com/$1 [L,R=301]
RewriteCond %{HTTP_HOST} ^domainname1\.com [NC]
RewriteRule ^(.*)$ http://www.domainname2.com/$1 [L,R=301]
This redirects domainname1.com to domainname2.com