Webshop built to fit existing design

I need a web shop for selling downloadable software. Design is taken care of in-house, but need help to build it. Latest versions of either Joomla/VirtueMart, PrestaShop or WordPress are preferred platforms, but if you got a better idea, I will listen. Besides the basic webshop features, these are important: Payment options: Credit card, PayPal, MoneyBookers and WebMoney (and ideally also Neteller, but not as important). Affiliate options: Custom referral link automatically generated, so users can earn money referring customers to the site. Recommend me an extension for this. SEO friendly Webshop and forum need to be single logon Option of using Facebook login Measures to protect the software from illicit downloads, secure them. Measures to counter hacking attempts. Easy to back up Breadcrumb navigation path Links to products should be: [login to view URL] Different discounts for user groups Different access for usergroups Different tax for different countries The website should be xHTML and CSS compliant, with commented code and be tested for cross browser compatibility. Integration of: Google Analytics E-conomic Easy to use backend, so I can add text, products, pictures, categories, updates. Maintain the site. To give a visual idea of what I need, pictures of 2 pages are attached. More pictures will be sent to the chosen freelancer. I do not currently have a theme, but will buy one if recommended. I will host the site and own the code. If performed well, repeat sales and maintenance and further development of site will be possible. (Multilanguage version of this site + 1 more shop are on the drawing board) Please only bid if you have experience delivering professional e-commerce sites, and be prepared to provide recent relevant examples of work and/or references. Also, you must speak English and provide regular progress updates, email or Skype.