Changing the displayed currency format is quite simple.
Just go in your Backend (BE) to the currency view (/administrator/index.php?option=com_virtuemart&view=currency). Choose the currency you wanna edit and you can easily change the currencyformat.
You can also define in the shop edit view (/administrator/index.php?option=com_virtuemart&view=user&task=editshop) with the accepted currency, which currencies are selectable in the currency selector module.
You can also define your own Currencies and define your own currency rate,
the currency rate 0 stands for automatically, it tries to use the xml from the bank. But you can also overwrite it with your personal rate. You can adjust your bank editing the URL set on top of the file (uses this file \administrator\components\com_virtuemart\plugins\currency_converter\convertECB.php)
You can also just add an own currency.