Edition for code of opencart CMS, removing text areas, creating new ones

Hi, project manager! My project for the site [login to view URL] consist of 2 parts. The 1st part is A) My online store is working on the OPENCART CMS and use 2 languages: Russian and English. Russian language is default, but I’ve prepared my requirements in English language with Russian translations for your help. When a user places an order on the site and clicks the "Check out" («Оформить» - in rus lang), the site redirects to the checkout page. It consists of 4 parts: - Information about product names, quantity, unit prices and total; - Customer; - Delivery method; - Payment method. The last 3 parts (Customer, Del method and payment method) have some areas that need to be filled by users. I ask you to edit the code of last 3 parts, where I need to remove some areas and create some ones: B) When user send an order I, as admin, usually receive the info letter. But characters in user’s e-mail such as @ displayed as “%40” . I need it ones everywhere (in information letter) displayed correctly. C) I will attached the database with postcodes Russia and program for open that base. If possible would like to see after the index has a buyer could automatically see the region and the name of the town. The column "Index" - a six digit ZIP code, after entering it should automatically appear 2 fields MORE INFO in the DOC file