How do I make currency translate

The currency will always display the same, regardless of the current language or page. You can change the way it display with the "format" and "symbol" options of your currency when you edit it via the menu System>Currencies, but you won't be able to do it on a per language basis.
A potential solution would be to install the extension Falang on your website and add a contentelement XML file in the folder administrator/components/com_falang/contentelements (similar to the ones already there) for the table hikashop_currency and then change the translation of the currency entry in Falang which would then dynamically load the translation of the currency on the frontend based on the language translation that you entered for it in the backend of Falang.