Hello,
1. We can suppose (not sure) that 'top-bar-text' and 'copyright' are options names. But usually, they are stored in general theme option. You should be able to find it by looking for the function 'update_option'.
2. You can put it wherever you want in your theme. Most people put it in header.php. That's useful if you want to put the switcher outside the menus and widgets sidebars. Otherwise the css rule is easier, as it's sometimes hard not to break the theme layout when inserting a new template tag. In any case, if you do some modifications, it's better to do them in a child theme.