Hi Ron,
You need to determine the exact town(s) of origin; "Austria" comprised quite a large area, and was sometimes used to denote any part of the Austro-Hungarian empire, including present-day Slovakia. If Frank and Jennie were immigrants, their origin(s) might be named in any of their following: death certificate, obituary, marriage record (civil and/or church), passenger manifest, naturalization papers, alien registration papers, newspaper articles (eg 50th anniversary write-up), maybe child's birth certificate. If they had siblings in the US, the same records for them could be searched.
The Latter Day Saints (Mormons) have microfilmed church and other records for places all over the world. Once you know where Frank and Jennie came from, go to
www.familysearch.org and search the library catalog (place name search) for microfilms for the pertinent town(s). That website will also tell you where the Family History Center nearest to you is located, where you can order (rent) and view the microfilmed records.
You likely will not find a "birth certificate." More likely, you will find a line in a baptismal register with all the information (date of baptism, maybe birth too, name of child, name of parents, perhaps address, name of godparents, sometime additional info such as baptized by midwife or born after father's death). Even if you were to request an official certificate from the church or government today, they would go to this same register (or a microfilm of it), and copy that information onto a modern form and send it to you.
I hope this info is helpful.
Julie Michutka
jmm@pathbridge.net