How can I use multiple templates in one site

Hi!

I have a problem. I`m developing a site that contains 5 different templates (this is done) everything is fine & looks ok, problem is that I want to change a template for a home site and 4 others parts of my site.
I`ve used a code:

<?php

if ($is_front) {
  include 'page-home.tpl.php';
  return;
}

switch (arg(0)=="o_firmie") {
default: $inc = 'page-o_firmie.tpl.php';  break;
}

switch (arg(0)=="szkolenia") {
default: $inc = 'page-szkolenia.tpl.php';  break;
}

include ($inc);

?>

If anyone could help me, i will be very thankful