Air conditioning systems are designed to work a specific area and must move a specific amount air through it to properly operate. Running extra ducts would take air flow from rest of the house. The solution often times is ductless air conditioning. This type of ac system consists of two parts just like a conventional ac system an air handler and condenser units. Condenser units are as always outside and depending on system desired can do both heating and air conditioning as well as handle several air handlers for zoned operation. Each air handler is a discrete unit that is permanently mounted on vertical wall which is connected directly with the condenser electrically and a refrigerant line set. These units can very in efficiency between 13 and 26 seer and can greatly vary in pricing between brands and desired functions.
Although in some situations traditional air conditioning is the best solution, sometimes its best to contact a professional for proper advise. As always we will be glad to guide you through the plethora of options of air conditioning.