If you have other gravestones, may I suggest that you post them on the ViewMate page. It was created for that purpose, and is really the best way to get a gravestone translated.
Here is my reading:
At the top of the stone, inside the Star of David, a two-letter abbreviation meaning “Here lie”
Dear mother and beloved grandmother
LEAH BLOCK of the house of SELTZER [in other words, this was her maiden name]
Died on the 17th of Kislev, 5730 [not 5760, as someone else read]
May her soul be bound up in the bond of life.
[This stone is a bit unusual, in that it does not include the Hebrew name of her father. It does include her last name and her maiden name, which is also a bit unusual. As to the date of death: the 17th of Kislev, 5730, began at sunset on November 26th, 1969, and ended at sunset on the 27th. The stone gives the secular date as being the 26th. This means that she passed away between sunset and midnight on the 26th].
Reb TZVI, son of Reb Hertz
died the 9th of Tamuz, 5723
May his soul be bound up in the bond of life.
[‘Reb’ is an honorific; it does not mean rabbi. As to the date of death: the 9th of Tamuz, 5723, began at sunset on June 30th, 1963, and ended at sunset on July 1st. The stone gives the secular date as being June 30th. Here, again, it makes it possible to narrow down the time of death to between sunset and midnight on the 30th.]--
Brooklyn, New York, USA