Changing the layout of excerpts is possible, but requires WordPress, PHP and HTML experience. If you're not a developer I'd advice against doing that on your own.
Sugar & Spice is translation ready theme. To translate open sugarspice.pot (located in languages folder) with Poedit. Translate the file and save in languages folder under name appropriate to your language (i.e. pl_PL for Polish).
Next, if you haven’t done so already, you’ll need to edit your wp-config.php file to set default language for your website. For example, to use polish translation, you’ll need to set your language in wp-config.php, like this:
define ('WPLANG', 'pl_PL');
wp-config.php file is located in the root directory of your WordPress installation.