Bidding, secret auction, tender

I have a site here

What I am after is for customers to leave a monetary value and add to a cart, as this page does, however when they have finished, rather than the cart go to paypal as this currently does, they would be required to enter credit card details that would be stored until the sale period of a week had finished. No one can see anyones bidding or offering.

At the end of the period we select the winner.

Behind the scenes I don’t think it matters if the cart generates a simple form where all relevant information is added and this then generates an email or is stored in a management system.

Any ideas weavers?