Split Categories to List into 2 columns?

Hi. I would like to split my categories into two column on this page: http://www.lasilhouettelingerie.com/shop/shop-by-designer-c-72 (instead of one long column)

Under configuration>maximum values I was able to change this: "Categories To List Per Row" from 3 to 18 to split my list in half. Now how can I put the second half into another column to the right? I was hoping to find this in the admin control panel.

"Categories To List Per Row" from 3 to 18 to split my list in half

Set that to the number to list per row which would be "2"

That still puts the names into one long column with two names a large space and then two more.

I am looking for two columns with half in each row (18 per row).

I want it like this:

Name1 Name19
Name2 Name20
Name3 Name21
etc... etc...

Not like this:

Name1
Name2

Name3
Name4

Name5
Name6

You still have not reset this to 2 - - -
Yours

<div class="categoryListBoxContents" style="width:5%;"><

Mine with 3 abreast

<div class="categoryListBoxContents" style="width:33%;">

I reset it to 2 and then changed it back because it did not work.

But now I changed it back to 2 so that you can see. Here it is:
http://www.lasilhouettelingerie.com/shop/

My code now show this:

<divclass="categoryListBoxContents" style="width:50%;">

It is still in one column.

In your stylesheet find this and change to left - - as float center is not a valid call

#logo, .centerBoxContents, .specialsListBoxContents, .categoryListBoxContents, .centerBoxContentsAlsoPurch, .attribImg {
    float: center;
    }

http://www.w3schools.com/css/pr_class_float.asp

Thank you that is what I was looking for. I appreciate your help!