A whole family of Helstroms in PA

I am part of a very large family of Helstroms.My father is one of 14 kids- Their Father's name Francis Helstrom.
His father's (my great grandfather) name i believe was Ifan Hellstrom.Francis is still alive and resides outside of Philadelphia.Our whole family is getting together soon for Christmas and I would love to know more about my heritage so that I may share it with my family. I dont know much about my background accept that my great grandfather (Ifan) came over from Sweden, but nothing before that.
Please contact me if you know more
Thanks
Lora