With great excitement, Mrs. Joe returns from shopping with the pompous Uncle Pumblechook and unwraps herself hastily, throwing her bonnet onto her back where it catches since the ribbons remain around her neck. She pronounces the name of Miss Havisham with pomp since Miss Havisham is known as
an immensely rich and grim lady who lived in a large and dismal house barricaded against robbers, and who lived a secluded life.
Because Miss Havisham is rich, Mrs. Joe anticipates that her asking Pumblechook for a boy to come and play is portentous:
...this boy's fortune may be made by his going to Miss Havisham's....
Here, in Chapter 7 there is foreshadowing that Pip's life at the forge is about to change. In addition, Dickens demonstrates how social status overrides any eccentricities. For, it does not matter that Miss Havisham lives alone and has a mansion in decay that is barred from the outside world. Mrs. Joe is simply excited that Pip is going to go to the house of a rich woman.
Basically, she brings the news of Pip's first "great expectation." She tells Joe and Pip that Miss Havisham is looking for a boy to come to her house to play. Mrs. Joe says that Mr. Pumblechook suggested Pip. So the news is that Pip is going to be going off with Pumblechook to Miss Havisham's house the next day.