Dropdown Navigation Menu listing custom categories in WordPress Header

Hi wordpress peeps,

I need a dropdown navigation menu in the header of my WordPress blog http://fatcowbusiness.com/ – What I have in the left column is way too complex so want to replace that with basically a horizontal dropdown menu placed below the header image.

Needs to be compatible with all browsers including safari. This plugin seems to have CSS menus as well as supporting older browsers but I can’t seem to customize it to what I want:
http://pixopoint.com/products/pixopoint-menu/

Even the standard WordPress Nav Menu’s in the newest versions of WordPress would be fine if it can just be customized properly – http://fatcowbusiness.com/wp-admin/nav-menus.php

I tried adding this code to my header.php file
<?php wp_nav_menu( array( ‘sort_column’ => ‘menu_order’, ‘container_class’ => ‘menu-header’ ) ); ?>

But it just lists plain text links, I need a dropdown menu, also I would need to “group” some categories under headings:

As far as appearance goes these sites look good:
http://foxsports.com.au/
http://www.linkedin.com/home?trk=hb_tab_home_top

So I need a dropdown menu in my header listing categories and groups of categories like this:
http://fatcowbusiness.com/images/fatcowbusiness-header.jpg

Need these categories/groups in this order:
Make Money with Facebook
Making Money with Twitter
Best WordPress Plugins
Top Web Hosting Services
Email Marketing
Search Marketing
Make Money by Blogging
Affiliate Marketing
Make Money with Youtube
Article Marketing
Business Services
>>More

Note that some of these are “headings” where multiple categories are grouped under, e.g.
Email Marketing
– Email Marketing Tools
– Email Newsletter Services
Affiliate Marketing
– Make Money Affiliate Marketing
– Make Money Affiliate Programs
– Making Money with Clickbank
Article Marketing
– Online Article Marketing
– PR Distribution Services
Business Services
– Accept Credit Card Payments Online
– Logo Graphic Design
– Online Business Cards Printing
– Outsourcing Services
– Shopping Cart for Website
– Virtual Office Space
– VOIP Phone Calls
– Website Builders
– Wholesale Suppliers
Search Marketing
– SEO Engine Optimization
– PayPerClick PPC Search Engines
– PPC Search Marketing
>>More
– Mouse Tracking
– Internet Marketing Conferences

I am currently using TwentyTen Theme which has been customized a bit to fit comparison tables and links on the categories pages.

I can pay a small fee so let me know ASAP if you can do this quickly or can recommend someone – if you are good have many other tasks for customizing various WordPress blogs.