Search a custom database and show result in search page

Hi
I was searching for days to get a solution. I have added my own table to word press. I want to search that table and display data from that table also. It has no relation with other tables of wordpress. I am trying to create a plugin.I have tried creating like this

function acts_search($content) {
if(is_search())
{
 $content .= "Helllllooooooooooooo!!!!";
}
return $content;
}
add_filter( 'the_content', 'acts_search' );

but nothing is added to the search result.
Is there any other way or any other idea. Any help is appreciated.
Thanks