Integrate Dispatch & Invoicing

Our web app is nearly ready, but the dispatch module and the invoicing module still act like strangers. I need the two connected so that once a job is dispatched and marked complete, its service details, dates, and quantities flow straight into an invoice record... (Budget: $1500 - $3000 USD, Jobs: API Development, Database Management, MySQL, PHP, Software Architecture, Software Development, Web Development, XML)