You may want to contact used auto parts retailers near you -- and even via the Internet not near you -- to see about finding a low mileage replacement engine. Work with a local repair shop, also, to acquire and quote out the cost of a replacement engine.
RepairPal Certified shops can diagnose and repair your 2009 Audi A4. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.