I think you've got the right concept with your DHTML menu. However, I'd scrap the code and redo the code from scratch. Dreamweaver code is horrendous at the best of times, and it's certainly not helping you in this instance.
What I would do if I were you is apply the inner bevel style to your main menu items, and your submenus only if/when they're hovered over. Load a plain background colour as default for your submenus and they'll fly out a lot more quickly.
To see an example of what I'm referring to, go to
www.tscst.org . The menu itself has a gradient (and a slight bevel), but the submenu is plain until each item in it is hovered over. Then you get the bevel coming out of it. I had it the way you did originally, and the speed of the menu was just horrible.