Final answer:
If a friendly settlement cannot be reached, Mr. Gardner should bring a civil suit against his neighbor for the garage encroachment on his newly acquired property.
Step-by-step explanation:
If a friendly settlement cannot be reached regarding the neighbor's garage encroaching on Mr. Gardner's newly acquired property, he can bring a civil suit against the neighbor. The neighbor is responsible for the encroachment and should be legally held accountable for the trespass onto Mr. Gardner's property.
The other options mentioned in the question, such as the broker, Real Estate Commissioner, and title company, may have their roles to play in the overall real estate transaction process, but the primary individual responsible for the encroachment is the neighbor who built the garage on Mr. Gardner's property.