6613 Items currency change US--CAD

On my site the payment for the service is through paypal. For some reason the currency is set to US dollar. I would like this changed to Canadian dollar. When customer wants to place the order (one item a time) he clicks on paypal button and that takes him to paypal for processing. If payment is success then he is able to proceed with completing the task.(I really don't have to explain this to You). From admin control we can add or change the name and price of each item. There is only 4 or 5 items on the site at a time. So basically all we want to change is that customer be able to pay in Canadian not US currency. Thansk,