Emigration records from the US were not kept. If she happened to have traveled back to Austria via England, there are some inbound and outbound British lists available on Ancestry.com.
Dear Ms. Sherman,
Thank you for posting your request on History Hub!
As the previous poster suggested, you may want to contact the Austrian State Archives or the Municipal and Provincial Archives of Vienna to inquire about historical passenger arrival manifests. As the vast majority of immigrants from the Austrian Empire would have used Hamburg, Le Havre and Bremen, we suggest that you search Ancestry.com or other genealogy sites for any digitized passenger arrival lists for those ports. There may be a fee for using Ancestry. Instead, check for access at your local library as many library systems subscribe to these sites, making them free for their patrons.
We hope this is helpful. Best of luck with your family research!