Disclaimer: Obviously, I own none of this Harry Potter stuff
The Weasleys had moved into Grimmauld Place at Dumbledore's request, shortly after the summer had started. A safe place would be needed for the Order of the Phoenix to meet, and someone needed to make sure it was ready. The house belonged to Sirius Black, who was busy rounding up the older members and would be back probably within a month.
The children had explored, claimed their rooms, and quickly made themselves at home in the 'haunted house.' Fred and George had found two rooms joined by a bathroom, and Ron had found a room that still had someone's things in it and walls plastered with posters, but one of the posters was a drawing of the Gryffindor seal, so Arthur had figured it would be fine. Ginny had found a room that also had its walls covered, but with drawings, and was empty of personal belongings save a bookshelf and an old locked trunk. Molly had not felt so at ease, and had tried to stay busy cleaning, cooking, etc.
The kitchen quickly became her refuge. It was the only normal part of this whole abnormal situation. Here they were, in an old manor that seemed to belong to no one, seemed to have been abandoned for years, and held numerous hints that Dark Wizards had been here, preparing for the eventual Order meeting.
Then she had found the rocking chair. It had been put up in a room to collect dust. Molly had cleaned it up and looked it over. It was beautiful, really. Simply made, it was plain, but had a hint of elegance about it. And of course, it seemed to have a story, though there was no telling what it was.
Why else would it have been abandoned, left to be forgotten? It had not been placed in such a lonely part of the house for no reason. It had been left there purposely, in the corner of the room.
It reminded Molly of the rocking chair she had left at home, and she sniffled, holding back tears. Why did all this have to happen? Why did You-Know-Who have to come back? She sat down on the chair, and relaxed. The chair had a soothing effect, and Molly felt that everything would somehow turn out right.
Molly had proceeded to convince Arthur to bring it to the empty space in the living room. Maybe he had sensed how important it was to her, and had quickly agreed to move it. It sat as if it belonged there, as if it had always been there. As if it were supposed to be a permanent part of the living room.
And gradually Molly got used, more or less, to the horrible place.