VAZ St.Pölten is located in the heart of Lower Austria, right on the A1 Westautobahn (western expressway). Just take the St.Pölten Süd exit and you're practically there!
After exiting the expressway you need to take a LEFT at Mariazeller Straße in the direction of the city centre ("Rathaus", "Zentrum"). After around 800m you'l reach a railroad underpass; drive through and then (in front of the WIFI building) make a sharp turn (180 degrees) RIGHT. You'll then be on Porschestraße. After another 800m (around "ÖBAU-Nadlinger") you'll need to take another LEFT into Kelsengasse. The VAZ St.Pölten headquarters are located about 400m further at Kelsengasse 9. There's a free parking lot for you to make use of directly in front of the building.