Accounting database

Ok I have a need for an electronic invoice book that auto numbers all my invoices everytime the appication is set up. also i need purchase orders to be linked to these invoices if they are required simply by the touch of a button, here is the business senario : a customer comes into the shop to buy an item, if we have the item all is well we fill in the custmomers invoice details they pay they get a copy of the invoice. If we do not have the item we need to be able to do all of the above but when we give the customer their invoice the next step to do is press the purchase order button and it duplicates all the invoice data into a related purchase order so the purchase order can be filed out. The purchase order data will need to be then added to a sort of history page (stock control) so once the items arrive at the store from the supplier they can be checked against the order an highlighted