Change width of boxes under navigation bar in Calotropis 1.5.2

For NaturalMedicalSolutions.com I use Calotropis 1.5.2. The site is still under construction.
I make profuse use of the Navigation Bar to list products and items.
The list is so long that it goes all across the page down and still continues.
To avoid that

I’d like to change the width of the boxes created under the navigation bar, i.e., the second tier of the menu, increasing the width.

I also would like to have the items on more than one column, say, two, three or four columns.
Please help, thank you.