Convert Existing ASP Website to PHP

I have an existing Ecommerce website which was written in .asp. It is based on EcommerceTemplate [login to view URL] and has been customized with some core code changed. I would like to Switch everything to Zen cart but The current website has an order system that automatically sends my orders to a distributor for drop shipping. It is time for me to convert. The old website just looks way out of date and has no flexibility. I cannot afford to have the existing website down for any length of time. I am hosted on a shared Win 2008 with a limited control panel. SQL and MySQL is available. The website will remain Windows based. I would need everything converted including some Jscript, Install on new or existing server with SSL & Authorize.net. Quality and completeness is more important to me than time. Before bidding please view my website. [login to view URL] I am available for any questions Two other past projects were completed using Freelancer. Both were 10 stars in each direction. BUDGET IS NOT FIXED AT $250 MAX. BID WHAT YOU FEEL IS APPROPRIATE.