Build me a customized invoicing

Build me a website that i can use for making invoices (for my self) i do a lot of invoices and i need a program to do the following. What i want is to add information on one page, I enter the details on one sheet and it appear on the invoice. I have more than one company and company invoice. I want to be able to add a new invoice template from one of my other companies and be able to use it in the program. ( please note not all invoice are the same, for example invoice number night be one the left on one invoice and on the other it might be on the right). I dont want my invoice to look the exactly the same. Heading Qty, description, unit price total. all editable. date, invoice number, customer name and address, unit, description, unit price are all editable. I also want a drop down menu for description, where i can pick the product/description. This should also fill in the unit price. Please note that the unit price change daily so i must be able to edit it, on the same sheet where enter details for invoice, so it is close at hand. We also save our invoice with the date and invoice number, output file must be pdf and html Please note we are in the UK so 20% vat will apply to invoice. I want all the information on one page so i can edit it to my need and then send it to invoice.