I have a percent Ionization Problem I really need help on.?

It is found that when a solution containing 39.2 grams of H2SO4 in 1000 grams of water is prepared, the H2SO4 dissociates completely into H+ and HSO4-1 and that 17.8 % of the HSO4-1 further dissociates into H+1 and SO4-2. Calculate the freezing point of the solution.