Foerster family

I was born Ellen Foerster. My father was Carl William Foerster born in 1905 in Lakewood NJ. His mother was Emma (Schmid) Foerster and father was Carl Wilhelm or just Wilhelm Foerster, also spelled Forster with the 2 dots over the o. They were from Germany. He in 1866 and she in 1873. In the early 1900's they were caretakers on the Rockefeller estate in Lakewood NJ. I am trying to find out more facts about them, and when they came to the US. I have little information. Any help would be appreciated.
Also siblings of my father were Anita and Alma.