Well, the Period allows us to work out the semi-major axis a:
a^3 = P^2
a = (2.415^2)^(1/3) = 1.8 AU
So we know that's the average. The perihelion distance looks by my judgment to be approximately 1/2 of the aphelion distance (or 2/3 of the semi-major axis): So Dper = 1.2AU and Daph = 2.4AU, roughly. A ruler and the (weird) scale should yield similar results I hope!