I was gonna say that you could use the "margin-left" and "margin-right" settings in CSS, but unfortunately, they only work for block-level items/paragraphs. In other words, it will only work for the entire line of text in a menu item(which is a paragraph).
You can however use nobreakspace( ) in your title name. Put it before and/or after the title name, and it will give more space in between. It may be a cheat, but it works fine =)
your_title