No css in website

I have installed your plugin, thanks.
It work well for me in the admin pages.

I write a personal theme but the tables don’t work in the website.
Structure is well generated, but css are not includes.

I found this solution (added in the header of my theme) :
<?php $url = plugins_url(); ?>
<link rel=”stylesheet” id=”wptg-jquery-ui-structure-css” href=”<?php echo $url; ?>/table-generator/css/jquery-ui.structure.css?ver=1.0″ type=”text/css” media=”all”>
<link rel=”stylesheet” id=”wptg-stylesheet-css” href=”<?php echo $url; ?>/table-generator/css/table-generator.css?ver=1.0″ type=”text/css” media=”all”>
<?php wp_head(); ?>

Is this the only way to make it working ?
Thanks