Add functionality in Magento Website.

PLEASE READ IT CAREFULLY BEFORE BID ON THIS. I have one magento website. It is market place website. I want to add one functionality. Where product price will show in INR in india and outside of India product price should be in $ For example if any product price is 100 INR and $ rate is 50 then in other country product price will $2. And admin have ability to add any % amount when it is show in other country. when user come on checkout page then currency will convert in INR only. Checkout url should be [login to view URL] as right now it moves to shopify store. If any customer open this website out of India Cash on delivery option will not show. Only payment via card, paypal and other option show to them. But no cash on delivery. Website URL is [login to view URL] Where you need to add all these functionality.