XML feed import into PrestaShop

We are looking for a well experienced php and xml developer with prestashop knowledge to import the products feed from supplier's end which is supplied in XML format and then export into Prestashop database. Stock level and prices will need to be updated every 15 mins via Cronjob. Also when an item is " Discontinued " from supplier's end, it should also be able to remove from our website. This project will also require you to add " Per category Margin " and download/upload the images direct from supplier when new item is added. You will also be responsible for migrating customers and orders into newly developed prestashop. At present we are using zencart but due to nature of work, we have to move to prestashop. To make your job easier, existing code can be supplied. We have 2 versions ( one for zencart and one for Interspire ) so it will be easy for someone who knows how to edit codes and make them work with Prestashop. We have been given xml document so full technical support is provided. For this project, we need well expert developer.