Dropdown menu [PAID]

I created my design in Photoshop and had it converted to XHTML and CSS then I made it work with WordPress however I now want to add a simple drop down menu for child pages of certain pages.

I tried the following code from this website however its not displaying properly and not on all pages. I need this completed as quickly as possible.

Here is my current test site: http://dfinnema.com/starke/

I am willing to pay for a solution for anybody that can find a good solution.