how config palm os to account software

I work in a small office that sell phone cards I do all the technical stuff the director want me implement.they do route sales they write all invoices hen the get to the office they input again the invoices I want to use palm so they just input how many cards the custumer want. and be able to print from the palm. when they come back to the office syncronize with quick books. I want to create inventory to know how many card I have on hand. if any body know how can accomplish this project. I appecite your help