Pretty sure this is who you're looking for::
1880
Warwick, R.I. Census:: (indexed as Sandborg)
Gustaf Sandborg, age 26, works in a bleachery, he and his parents were born in Sweden
Augusta, age 24, she and her parents were born in Sweden
Helma, age 4 mths, born in R.I.
1900
Warwick, R.I. Census::
Gust
Sandberg, born Mar 1855, immigrated 1873, born in Sweden, married for 21 yrs, works in a bleachery
Augusta, born Mar 1855, in Sweden, immigrated 1874
Claus E., born Feb 1880, in R.I.
Oscar C., born Aug 1882, in R.I.
Clarence H., born Mar 1884, in R.I.
Frank A., born Dec 1886, in R.I.
Richard O., born Jan 1893, in R.I.
Earnest A., born Aug 1897, in R.I.
1908 City Directory lists
Augusta as widow of Gustav
Augusta is in the 1910 & 1920
Warwick Census, as a widow. I can't find her in the 1930 R.I. Census