The list of supported currencies can be found on Accepting International Payments
Currencies which can be configured in your Barclaycard account are determined individually - to check the currencies supported by your account, go to the Barclaycard panel, section Configuration/Account/Currency.
If a payment is supposed to be transferred in the same currency that the one chosen by a buyer, the currency must be set as a billing currency in ADMINISTRATION/Currency setup/Currencies configuration for page.
The description of each configuration field can be found in the section How to run processing payments through Barclaycard. The full content of the page is available for registered users only.