Dynamic Categories - subcategories

I would like to create a dynamic script to add first level categories on the navigator bar (LIKE shown in the link with MEN,WOMAN, ACCESSORIES) and then slide down like it is in the site with sub categories.
This is hard coded now. at www.feerol.com/mydev2

This is my first post and would like to seek help from anyone one who have done a similar implementation

Please advise