There is a "Help" button on which you can click on each screen of the backend where it explains what the settings do.
There, you will see that:
Format : The way you want to display the symbol (basically you will have %i which will display the currency code as symbol, %n which will display the currency's symbol and %ni which will display both). For more information, you can look at
www.php.net/manual/en/function.money-format.php
So basically, just change that format option of your currency as explained.