Different icons next to links…

Hi. Total newbie here, and I need a little help with something. In the side bar of our site, we have three different sets of links. One is for links to our “Site News” posts, one is for our “Latest Stories”, and the last is for links to our “Latest Forum Posts”.

We would like to display a different icon (bullet image?) next to each set of links, but after trying everything we can think of, we can’t figure out how to do so. If anyone could help, it would be greatly appreciated.

BTW…using a modified Revolution Church theme, in case that makes a difference.