Tweak in exisiting website: add sublevel in tree structure

hi, I have a website, oscommerce/PHP based. Need an small update of my website. we sell products. we have several product categories for several car brands. We need to add now an extra sublevel containing brand MODEL. Right now the tree structure of the menu in both front and back-end is : A ......AA B ........BB C D E This should become: A ......AA ...................AAA B ........BB ..................BBB C D E This sublevel needs to be added in the admin area as well, so that we can select both the BRAND (as we already do) and also the brand MODEL. The entire sublevel page layout can be scraped from my supplier website, which is in AJAX. So only freelancers with experience in OSC, PHP, AJAX en scraping please. In addition some minor tweaks: - To get the download of documents for customers working (functionality is there, but not working, attrib function in OSC). - to be able to highlight unprocessed orders in admin area - to transform a slider which I currenlt have if your work is perfect, on time and reliable, beyond expectation...we might work on future maintenance issues...it's up to you