Website to showcase and sell software product

I have an outlook add in which I plan to sell via a website. For this I need someone to design an excellent product centered website to showcase the software. The website should have an area where the user can buy a license for the software from. 1. I am OK if you can design the overall HTML based look and feel of the website and how it should look. 2. If you can deliver the whole solution with the payment gateway integration built in I will consider that too. 3. I need a logo designed too for my company's name to put on the site. Here are some of the salient requirements 1. The website should be responsive. 2. Attention should be paid to combine and minimise javascript resources, CSS handling , image sprites etc. to increase the site efficiency. 3. I can consider a ASP.NET MVC or Wordpress project both. 4. The payment gateway should be able to handle international credit cards as most of the business would be from customers in western countries. 5. During the payment process the website will need to make a POST call to a webservice with the details of the payment processed. More can be explained as needed. 6. The site will host some demo videos and FAQ page so design should take into account all of that.