hi there sheena!... well, in my opinion,yes, web template may also help increase your sites' traffic...coz if you have a good quality web design and conatins interesting articles and contents, well, it is not impossible to attract readers/ browsers to go to your site....
kindly read this article for
10 Effective Website Promotion Techniques:
http://www.kiwisgraphics.com/sitepromotion5.html
hope it helps...