Please refer to an Austrian representation in your home country for any questions regarding visa. You'll find a list of Austrian representations on the website of the Austrian Foreign Ministry. Please note, that visa applications can only be made from abroad (if requested for your country). It is also not possible to prolong your visa in Austria.
In the following a noncommittal list of countries, whose citizens do not need a visa for the entry into Austria:
Andorra | Argentina | Australia | Belgium | Bolivia | Brazil | Brunei | Bulgaria | Chile | Costa Rica | Denmark | Germany | El Salvador | Estonia | Finland | France | Greece | Great Britain and Northern Ireland | Guatemala | Honduras | Ireland | Iceland | Italy | Japan | Canada | Korea | Croatia | Latvia | Liechtenstein | Lithuania | Luxembourg | Malaysia | Malta | Mexico | Monaco | New Zealand| Nicaragua | Netherlands | Norway | Panama | Paraguay | Poland | Portugal | Rumania | San Marino | Sweden | Switzerland | Singapore | Slovakia | Slovenia | Spain | Czech Republic| Hungary | Uruguay | Vatican | Venezuela | United States of America| Cyprus
For all other countries visas are requested. Please inform yourself anyway at an Austrian representation in your country.