Creation of website...

I need to build a professional functional website. The design is very important and it must look beautiful and professional (CRITICAL). The main idea is to show dynamic pictures to clients or users from several products being offer by different business or sellers located on different cities. Each business or seller must have their own section with general information and photos of their products including a geographical functionality to be shown on a map. Users must be able to upload pictures of the product they bought and post comments about them, they also must have the opportunity to rate every business and product they have bought (comments and pictures must be check before posting by a page administrator). Users must be able to search for products with several filters and have the opportunity to buy them. When a user buy a product, the page must be able to notify the seller via mail and/or sms mobile message (very important because some sellers doesn't have email), users must have the opportunity to pay it online with different payment options. Also the sellers must have the opportunity to post their products(with payment) online so clients can buy them. Users must be able to register and post via social networks. The website must be able to be display perfectly with full functionalities from any mobile device such as cellular phone or tablets. It also must be designed that in a future there is going to be mobile applications for this website. I am also a programmer so i know what i am doing and what are you doing, just i dont have the time to do it myself, so dont try to dumb me in any way. I want a professional job, with great communication skills in english or spanish and the ability to communicate through skype in working hours. I will help to design the database and canvas of the page. I also will pay the hosting service of my choice and at the end i will need the full control of the code with a signed letter from you. Please if you can provide the cost as fixed price. The time is not important for me because i want a professional site not a hurry bad site.