Hey robcsw,,just think of it this way: your 'website' is like your 'store'. Your 'shopping cart' is like your 'cash register'.
You cant sell much if the customers have no cash register to go to and check out...
You need to get some shopping cart software installed and incorporated into your site..Also you should be able to get a paypal button linked to paypal if that is the main method of payment you intend to accept...Or clickbank,,something of that nature..
Visit some of the 'ecommerce' sites and they will have some options for you..