Need help with Sandin family from Sweden

Hello everyone! I recently found this site and am very excited with the info i've already found. I really need some help tracking down the Sandin family from Sweden. Peter D. Sandin came to Ellis Island from Sweden in June of 1903. He came here with his wife Anna S. Sandin. They had a son in the USA on August 5th 1913 his name was Carter William Sandin. He had a sister named Cagsa A Sandin, she was born around 1919. They came to Ellis Island from the port of Copenhagen on the ship Hellig Olav (Scandinavian America Line). Carter W. Sandin is my great-grandfather. I'd really, really like to learn more about the Sandins that remained in Sweden, and also what ever happened to Peter, Anna, Cagsa, and Carter. My family is not real forthcoming with information. I'm trying to find this info out on my own. It's really important to me. THANK YOU SO MUCH!!!! [:)] [:)]