Issues with currency in Global Store Checkout Process

Hello,

I set up a subsite for a merchant in London - their subsite Store Settings is set to the British pound but on the products page, it shows the dollar sign. During the checkout process, I can't reach the payment page either since her account does not accept payment in US dollar. Here is the product page:

http://www.fitguana.com/jenniferdevonshirebodytransformationcoach/store/products/12-week-custom-transformation-program-by-jennifer-devonshire/

Thanks!

Sander