Help adding an image to wordpress theme.

[chrisxuk]

Hi, basically i'm using this theme on a wordpress blog - http://wordpressthemesbase.com/detail/986.html

and where it has the RSS logo on the nav bar at the top, i'd like to add this image next to it linking to my twitter page.

Tried a few things, but just got the same problem, where instead of the image appearing it just has a link called twitter to my twitter page

Thanks