Harold, this site may be of use:
Austria: Index of All Pages
At the bottom of the page are links to other sites, but I can't find anything immediately which shows the Arms going back to the beginning.
The book
Lines of Succession - Heraldry of the Royal Families of Europe by Jiri Louda and Michael Maclagan (Orbis Publishing London, 1981) is a must-have for coats of arms (or more correctly, shields) from way back to the present day, as well as extremely detailed lines of descent. If you can get hold of a copy, this book is a treasure-trove and thus highly recommended.
For a descriptive of the original arms I quote from page 150:
"The Duchy of Austria was a union of the two districts of Upper and Lower Austria: the arms of the latter have five gold eagles with red feet on a blue shield, and are sometimes styled Austria ancient. They have been overshadowed by the white bar on red of Austria modern, one of the historic blazons of Eurpoean heraldry, and long linked with the Habsburg dynasty, who virtually abandoned for it the use of their ancestral arms, a red lion on gold with a blue crown."
Here is the Arms of the Counts of Habsburg (the red lion on gold with a blue crown) and some variations of the more "modern" Austrian arms: