You would normally run a reference chromatogram by injecting known amounts of the compounds you are measuring. From the peak areas you can determine moles of compound per unit peak area. Once you have this, you just have to multiply each peak area in your sample chromatograms by its corresponding mole/pk area factor to convert the peak areas to moles.
Or, another procedure, did you spike your samples with a reference compound? 1,4-dioxane has been mentioned here before in this regard. By comparing the areas of the sample peaks with the dioxane peak, you can calculate the amounts of each compound that way. You would need to know how the peak areas of the various compounds relate to the peak area of 1,4-dioxane (or other reference).
Steve