To change you currency, open your local config.php and look for the following
/*
This is the unit of money. For non-dollars, use :
Dollars ($), enter "$"
Euro (€), enter "€"
Yen (Â¥), enter "¥"
Pounds (£), enter "£"
For example, to set EUROS:
Config::Set('MONEY_UNIT', '€');
*/
Config::Set('MONEY_UNIT', '$');