I cannot tell you what changes to make as you will have to decide what fits best with your template - however, I have a suggestion to start with.
First of all, what you are talking about are not reviews, but comments. The page you linked to is a review page with a mostly blank review and the page is filled with user ratings from the comment box. This is important as it determines which template needs to be edited.
Second, it looks like your problem is that the comment template has the name set to be 25% of the width of the page and so any name which is longer than 25% will require two lines. You could think about changing this to a higher number (30%, 40%, etc) or change the design so that the width changes dynamically. Infact there are a few ways to change this and each has benefits and drawbacks.
You will want to edit this file:
I am not quite sure what you mean by a coding plugin. Are you asking about a joomla plugin? The file needs to be edited directly, this cannot be done from joomla. It is done with a plain-text editor. Not with WORD. Notepad or textpad, or notepad++, etc. You download the file using FTP or there are also file management joomla extensions. Edit it and then replace it.
If you are looking for someone to teach you PHP or HTML then I'm sorry but that is not for me. However, for a simpl fix you should see a line similar to:
<th width="25%">And the 35% can be increased.