Design In UjCategories
Archived
Most likely, changing the size of things will be done in your skin css. You could also override the template by copying modules/ujCategories/templates/menu_buttons.tpl to your active skin directory and renaming it as ujCategories_menu_buttons.tpl
For adding an ad column, I'm not sure that will be possible without building a template to use. It may be simpler to check for ujCategories in the skin and add your column there. Can you be more specific about what you wnat to add and where?