Checkout Page Needs Additinal Info

Hi, I need the 'Your Invoice Information' page of my website modified to enable customers to add the number of passengers travelling, their airline or cruise ship arrival information, the hotel name and address they will be staying at, and the airline or cruise ship departure information. The layout of the page will have the customer enter their invoicing information at the top of the page, and then the arrival and departure details in a form underneath this. If it looks as if the page may end up being too big then I would be happy for the customer not to enter their invoicing info on my website and just do that when they are re-directed to the PayPal website where payment is taken. Please let me know how long this will take you to complete as I would like it done asap. Website can be located at [login to view URL] Thanks