WooCommerce / Other E-commerce plugin with Forex Pricing

Hi guys, I need a little insight from you on which WP E-commerce plugin that suitable for me.

I have an online shop that sell goods to outside the country, therefore the price will continuously change depends on the Forex currency rates.

Is there any plugins that will set the price in USD, but the website will show in foreign currency based on the current value (that I set).

Or, every product are priced by variable (price 1, price 2, price 3), and I can adjust the value of those variables, that will adjusted on all products assigned to it?

Or any other tricks that will help to make it easier to dynamically change the price in regular basis (probably once a week / month).

Thank you!