Here are the two reactions you did (see message 2 of this thread to see where they fit in). For the time being I'm not specifying the signs of Qreaction.
HCl (aq) + NH3 (aq) ––�?gt; NH4Cl (aq) Qreaction = 44718.6 J (message 8 of "Enthalpy problem")
NH4Cl (s) ––�?gt; NH4Cl (aq) Qreaction = 15428.82 J (message 5 of this thread)
Note that the Qreaction values are the per one mole values. That corresponds to the coefficients in the reactions: 1 in front of HCl and NH3, and 1 in front of NH4Cl (s) (the ones are not actually written which is normal). In chemical calculations, the coefficients in the balanced reactions are the moles of reactants and products. That is why you divided the heats of reaction by the moles of HCl (aq), NH3 (aq), or NH4Cl (s), so that the values correspond to the two reactions as they are written.
Now, instead of saying "Qreaction", we will say "ΔH". They're the same numbers, but you have to be careful about the signs. ΔH is positive for endothermic processes and negative for exothermic processes.
Once you have filled in the ΔH values for these two reactions correctly, you will be ready for the Hess's law part. 
Steve
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