Four options here:
A) use Joomla's native before, after or no. Then go into your home menu item and add a browser title. It will STILL use the before, after or no, but at least you get a custom name out of it. So it'll look like:
Providing Service for 100 Years - Company Name
B) Add this code below your open body tag:
<?php
$app = JFactory::getApplication();
$this->setTitle($this->getTitle().' | '.$app->getCfg('sitename'));
?>
This gives you the option of using pipe breaks instead of the dash, or some other character of your choice. You can also instead of using sitename, can put something else in there and have it append to all browser titles.
Providing Service for 100 Years | Company Name
C) Set your Joomla to no. Manually write all menu item browser titles. Not horrible for smaller sites. Really awful for larger sites.
D) I haven't tried this, but I think it would work. In theory anyway. Add an id to your homepage.
This goes above the doctype:
<?php
$app = JFactory::getApplication();
$menu = $app->getMenu()->getActive();
$pageclass = '';
if (is_object($menu))
$pageclass = $menu->params->get('pageclass_sfx');
?>
And this replaces body
<body id="<?php echo $pageclass ? htmlspecialchars($pageclass) : 'default'; ?>">
Now add a class to your menu item. It will show up as the body ID. NOW, use the code provided in option D, and throw a php function around it prevent it from running on the body ID of your home page (sorry I don't know how to write php or I'd do it for you), then fill in the browser title in your home menu item. Everything else will get your site name appended, but the home page.