Thanks for your answer.
I used fire bug and confirmed that the theme css is providing the style, because I put a different color to the font of the breadcrumbs and It changed all the links in the theme.
Other thing I noticed on firebug is that the style sheet providing the codes, is name style3.css. however from the wordpress editor, I can access the sheet called style.css, where I pasted the code greencode gave me, however nothing changed on the breadcrumbs.
Sorry but I'm amateur! Any idea on how I can finally change the style of the breadcrumb font?
My site is under construction at the moment, but if you wish I'll put it on line for you to have a look!