+1 on everything CPFITNESS says!

Another consideration is that the current wheels are likely 27", which are 4 mm larger in radius than 700c. So you may need new long-reach brakes, but you should certainly measure to see if the brake pads can be moved down. Tektro has some nice long-reach double pivot brakes that people swear by. But the local bike recycler may have some good center-pulls that will work well, too.

The cottered steel crank on that thing is a real anchor- you can save a bunch of weight by changing to an alloy crank. Be careful choosing the bottom bracket- I don't know if Steyr were Italian, Swiss, French or English threading, all of which are different and incompatible.