Yes as govpatel said, for a dropdown just indent the sub-menu items.
If you are using the new menu system then Appearance > Menus, iy it says you theme supports menu in x locations, then create a new menu and add your menu items.
If you do not have the new menu system and want sub items, then Admin > Pages > Pages, then ‘Quick Edit’ the child page and assign a ‘Parent Page’ name, then check your menu.
If you want a ‘Second Menu’ then code is the way to do this, it is not that hard if you follow one of the tutorials.
If you are still stuck then ask the theme author, change the theme or pay someone to edit the theme, it is less that an hours work so would not be expensive.
A quick look and the theme is for WordPress 2.9, the new menu’s came with Version 3.00, so try adding a new page and assign a ‘parent page’
HTH
David