You know what the SO_{2} is oxidised to? SO_{3}^{2-}? SO_{4}^{2-}?

The last you have said. It's the only possibility, think about it. Which is the n.o. of S in SO

_{2} and in SO

_{3}^{2-}? It's the same. [

]

So S is oxidized to +6, which means SO

_{4}^{2-} in water solution (or HSO

_{4}^{-} in strong acidic solution).

By the way, the reaction from vanadate and SO

_{2} is exploited industrially to make H

_{2}SO

_{4}; vanadium +4 is then re-oxidized by air to vanadium +5 and so it acts as catalyzer.