If you know [itex]E[/itex], then you can calculate [itex]\Delta G[/itex], as you have done already. You also know that [itex]\Delta G = \Delta H  T \Delta S[/itex]. But, this leaves you with two unknowns.
Perhaps you can calculate some more values of [itex]\Delta G[/itex], and then solve for [itex]\Delta H[/itex] and [itex]\Delta S[/itex]? Hint: they've given you a piece of information that you haven't needed to use yet :)
