I own a bicycle by the name Senator, manufactured in Austria, by the Senator company. I have had the bike for over 35 years. I Would like to find out any information on it.
Looks like Senator is a store brand bike from the 70's. They did rebadge Puch branded bikes which were made in Austria, as did Sears.
It probably has cottered cranks, a three speed internally geared hub, and a twist shifter on the handlebars.
If it has sentimental value then by all means rebuild it, but its not especially rare. If you just want a bike to ride, it might be cheaper, less work, and give you a better ride to pick up a slightly used modern bike.