The width of the site is controlled in rectangle_top.tpl.
To move 'pieces', you need to edit home.tpl and move the includes where you want them. For example, to move the manufacturers, you need to move this piece of code under the catetegory include:
Code:
{if $active_modules.Manufacturers ne "" and $config.Modules.manufacturers_menu eq "Y"}
{ include file="modules/Manufacturers/menu_manufacturers.tpl" }
{/if}