Multi currency Shopping cart module

I want to add currency converter with country list or flag to my website, so that prices will be changed according. Using visitors’ IP addresses, the module should automatically identify their geographical location (country) and pre-selects currency and language that corresponds with the detected country. This also should work with shopping cart and customer will need to select payment gateway that will accept payment in that particular selected currency. this could be automatic or static exchange rate added to our admin end and shopping cart so we can set price for each product and customer can make payment on the currency and payment gateway for the currency. In the admin there is already a static currency conversion module but does not interact with the shopping cart.