This is the reaction:

Calculate heat of formation for .6C + .3O2 -> .6CO at 1300K

I know that I can get heat of formation for standard states on a table. How do I go about solving heat of formation for non-standard state reactions? Do I have to use an integral with the Cp values and then do products minus reactants? I am trying to solve for Enthalpy of the reaction, but I am stuck how to calculate heat of formations for non-standard state reactions. I appreciate any and all help to understand this.