I wrote this multicurrency module and paypal payment gateway module. Please test! thanks.

uc_fm_multicurrency and uc_fm_paypal. First module enables multicurrency for products, orders, history, etc. Presents a block for currency selection. Second module is a multicurrency gateway for paypal. Sandbox tested. Supports Paypal standard, paypal express checkout, and paypal payment pro.

Please post here if this works for you.