How to change text on checkout pages

-- url of the page with the problem -- : sycpb.org/index.php?option=com_hikashop&...tep&step=1&Itemid=73
-- HikaShop version -- : 2.3.5
-- Joomla version -- : 3.3.6
-- PHP version -- : 5.3
-- Browser(s) name and version -- : Firefox 35.0.1

I need to change the address formats to the US standard (postal code follows state name). Also, there is a message at the bottom of the page that says to write the order number on the Back of the check -- I want it to say to write it on the FRONT of the check. How do I do these changes?