To add to Kim's advice, I'll clarify a piece of information you didn't mention:
PayPal offers several kinds of services:
a) pay via PayPal -- where customers visit the PayPal site and supply their credit card/payment information there before returning to your site to complete the sale.
Customers have the option of paying with their credit card, or if they also have a PayPal account, then they can optionally use their PayPal funds to make payment as well.
PayPal Express Checkout or their older less-sophisticated Website Payments Standard services offer this funcitonality.
b) as direct card-entry within your website -- where your site collects their payment card details and processes the credit card in the background thru paypal while the customer waits for mere seconds. The customer NEVER knows that PayPal was involved in the transaction. You must have your own SSL certificate on your site for this.
Payflow Pro and PayPal Website Payments Pro both offer this service. PayPal's website can give more details on the pricing.