Yesss! offers 1 GB traffic with a validity of 12 months and 2 GB with a valitidy of 1 month, both for € 20.
A1 also offers 1 GB valid for 12 months for € 20, while providing better network coverage.
Telering has the very same tariff plus a 512-MB-pack for € 20, which is valid for 12 months.
Other Austrian operators do also have comparable tariffs. Austria probably has the cheapest mobile tariffs in the world.
There's no big difference in pricing among their operators, so let the local coverage decide. SIM cards are sold nearly everywhere.
For outgoing calls from Austria, I do recommend
eety, who have very low rates for international calls. E.g. calling Russia costs € 0,099-0,119/min.