Need help in locating origin of families named Brilla and Tharta

My mother’s parents, Michael Brilla and Pauline Tharta Brilla, arrived in the U.S. sometime around 1900. Census reports note Austria as their birth country and Slavish as their nationality. My grandather’s military registration in 1942 lists Tovsa, Austria-Hungary as his place of birth. Would appreciate help in finding the exact location of Tovsa.