Looking for Wortman

I have traced our branch of the Wortman family back to Easton PA in the early 1800's. The family took a flat-bottom boat down the Ohio, up the Mississipi to the Rock River and settled in Winnebago county around Rockford Illinois in 1848. Elizabeth Wortman b:1776-PA d:1856-Il, had a husband named David but I can find no information about him. I would also like to find the immigration date to the US and whether we cam from Holland or Germany. There has been some mention that th name was Van Wortman (Dutch)