Gibbs energy calculation

Questions
#1

How to calculate Gibbs energy (G) from a frequency output file?

#2

This is printed (at T = 298 K) at the end of a vibrational frequency job, e.g. for H2O molecule at the HF/STO-3G level I get:

   The Molecule is an Asymmetric Top
   Translational Enthalpy:        0.889 kcal/mol
   Rotational Enthalpy:           0.889 kcal/mol
   Vibrational Enthalpy:         15.297 kcal/mol
   gas constant (RT):             0.592 kcal/mol
   Translational Entropy:        34.608  cal/mol.K
   Rotational Entropy:           10.673  cal/mol.K
   Vibrational Entropy:           0.001  cal/mol.K

   Total Enthalpy:               17.667 kcal/mol
   Total Entropy:                45.281  cal/mol.K

(You can tell it’s T=298 K based on the value of RT.) The value of G at T=298 K is directly computable from the values of H and S that are provided. If you’d like G at a different temperature, then you need to recompute U, H, and S based on harmonic partition functions from the vibrational frequencies that are given.