The ET_CurrencyManager extension will not help with this selector.
To change this part, you need to change template currency.phtml This template is in the base theme here
/app/design/frontend/base/default/template/directory/currency.phtml
but you need to copy this file to your theme or find this template in your theme
/app/design/frontend/default/YOUR THEME/template/directory/currency.phtml
And then change the code
<?php echo $_name ?> - <?php echo $_code ?>
to
<?php echo $_code ?> - <?php echo Mage::app()->getLocale()->currency($_code)->getSymbol() ?>
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