You didn't say if you'd found census records for the family, so I took a look myself. (Name spellings are as they appear in the record.) In the 1920 census for South Milwaukee [ED 312, sheets 4B & 5A]: Charles, Anastasia, and children (Julia, Lucile, and Felicia) were living with Anastasia's parents, Joseph and Julia Cwiok, and her siblings, Eleanor, Jerome, and Josephine. Joseph, age 56, was born in Galicia (Austrian-occupied Poland). His year of immigration and naturalization status was left blank, and his native tongue was Polish. Julia, age 43, was born in possibly Germany or the German partition of Poland. It looks like "Un" [unknown] was crossed out and Ger written in. Her native tongue was German, and her year of immigration and naturalization status simply say "Un." Charles Falkowski, age 32, was born in Bransk, and his mother tongue was Polish. He immigrated in [what looks like] 1906 and had filed his "first papers" to become a citizen. Anastasia, age 22, was born in Wisconsin, as were her siblings.
The 1930 Census [ED 103, sheet 18A] is a little more helpful in terms of marriage and immigration info for Theofil and Anastasia. Theofil was 25 when they married, and Anastasia was 16. Theofil immigrated in 1905 and was a naturalized citizen. They have two more children by this time: Edward and Jerome. Living in the same multi-family dwelling were Anastasia's parents and her siblings, Jerome and Josephine. Joseph Czwiak immigrated in 1886 and wife Julia in 1876. They were naturalized citizens. Joseph was 28 when he married, and Julia was 16.
Since they married in the US, you could try locating a church marriage record which would likely have the names of their parents and where they were born. Civil records aren't as detailed church records and tend to be less accurate in spellings of surnames and birthplaces. You don't want a marriage certificate issued by the church but a photocopy of the complete entry in the church register. Certs are issued to prove the event took place and often don't contain *all* of the info written in the book.