These words were addressed to Mona da who was living here. But She has clearly said that Sri Aurobindo and Herself live in the heart of all who love them and respond to their prayers.
In a general way, the Immanent Divine dwells in every heart but He assumes the form through which we approach Him. Besides for the purposes of the play in Time He takes upon the form in which the Avatar descends to redeem mankind. These are the eternal truths that need to be always remembered.
What She has spoken above is with regard to the Samadhi meaning thereby that He has taken that place as the physical ground just as in His room. It is His most concrete earthly abode. However He dwells permanently in the subtle physical and not tied to the material body acts with a much greater power and universality. The Sacred Relics carry His divine vibration that radiates around and touches and helps in the transformation of earth and men.
But His Presence is everywhere and anyone with a little opening and faith can access and receive the needed help regardless of the place one lives at that moment.