Short answer: use the formula for ΔG in terms of ΔH, ΔS and T.

Longer answer: The temperature-dependent part of ΔG is the change in entropy ΔS multiplied by the temperature. You've just worked out the ΔG and the ΔS for a given T, so from those you just need to work out the other term, the change in enthalpy ΔH. From there you can work out the Gibb's free energy at any temperature just by plugging the values back in to the equation.

ΔG = ΔH - TΔS