Attach the credit card to your Paypal account.
Most sellers do not have merchant cc accounts and use PP instead.
The currency of your card is not important. If you buy from France, for example, you will be charged in euros, but it will show on your card in USD.
Just in case, when you say you have a USD credit card, is it from a US bank or from a Canadian bank, but denominated in US dollars? They are different things and have different charges.
The PP account backed by a credit card (in any currency) gives you the most Buyer Protection. You are covered by eBay, by Paypal and finally by your card company. Suspenders and belt and duct tape.
