Don't have the book, but do have some info on the Poraths and Hellers, since I am descended from them too. Don't know if you have any of this:
Death notice for Johanne Wilhelmine Caroline Giese Porath (aka Wilhelmina Porath).
Died--on Thursday May 2nd. Mrs. Purad.
The deceased had been a long suffer from rheumatism in its most malignant form. She leaves two daughters Mrs. A. Heller and Wm. Ladevig to mourn her demise.
--Herald Advance, Milbank, SD, May 10, 1895, page 8.
Erdmann Friedrich Ferdinand Porath was born on April 15, 1822 to Johann Friedrich Porath (b. abt. 1787) and Marie Elisabeth Bartel (b. abt. 1794). Johann and Marie were married July 27, 1814. They were from Noeblin (church records out of Steinhofel). Erdmann had 6 siblings: Friedrich Wilhelm (1817-1818), Eva Eleonora Dorothea (1818-?), Johann Friedrich Wilhelm (1821-1821), Johann Friedrich Wilhelm (1826-?), Wilhelmina Caroline (1832-?), and Johann David (1835-1837). Still can't find a marriage record for Erdmann and Wilhelmina.
Found all three daughters birth records and the Vogelsang/Porath marriage record in church records in Woltersdorf (Silbersdorf was the town they were living in). Didn't find any other siblings.
Found a ton of other Poraths, some Ladwigs, and a few Vogelsangs from those church records. No Hellers from this line were in these records since the church records were Lutheran and Andrea's lineage was Catholic.