Want a navigation menu system similar to tabs

Hi, I'm using this theme on my site.i wanted to have a menu system in such a way that sub menus of the parent menu do not open the way they open in a drop down kind of menu but instead they should open in a tab like menu.(please see the attached image) I'm a noob as for as programming is concerned.i don't know how i can create the above mentioned effect.can i do it by using modules like nice menus or YUI?
Please help
Thanks for this great theme.
Ritesh