By defaut in admin panel on dashboard listed last 5 orders but currency code in this reports retrieved from base currency setup for store instead current order

    $baseCurrencyCode = Mage::app()->getStore((int)$this->getParam('store'))->getBaseCurrencyCode();

If you need show the right currency code follow next steps:

Copy file

../app/code/core/Mage/Adminhtml/Block/Dashboard/Orders/Grid.php

to

../app/code/local/Mage/Adminhtml/Block/Dashboard/Orders/Grid.php

Paste

        $this->addColumn('total', array(
            'header'   => $this->__('Grand Total'),
            'align'    => 'right',
            'sortable' => false,
            'index'    => 'revenue',
            'type'     => 'currency',
            'currency' => 'order_currency_code'
        ));

instead

        $baseCurrencyCode = Mage::app()->getStore((int)$this->getParam('store'))->getBaseCurrencyCode();

        $this->addColumn('total', array(
            'header'    => $this->__('Grand Total'),
            'align'     => 'right',
            'sortable'  => false,
            'type'      => 'currency',
            'currency_code'  => $baseCurrencyCode,
            'index'     => 'revenue'
        ));

difference in line 'currency' => 'order_currency_code' instead 'currency_code' => $baseCurrencyCode.