You propably mean Olszanica that belonged to Stefkowa parish. There are records for this parish (but do not have to include Olszanica) since 1784 to 1844 in Przemysl archives and births 1844-1890 and deaths 1845-1889 in Sanok archives. There are death records just for Oszanica for years 1852-1909 in Sanok archives. Later records in civil registry office. You may also ask in Greek-Catholic archives in Przemysl.

Zbigniew