Finding moles and concentration in a titration problem?

Unknown molarity of KHP is titrated with 0.1M NaOH. It took 37.6mL of NaOH to titrate 25mL of KHP that was pre-mixed with 20mLof distilled water. Moles of each ion has to be calculated and I know that moles = molarity(M) x volume(L) but I'm not sure which volume to use. For example, to find the moles of Na+, should I use the volume that NaOH takes to titrate the solution or the total volume of the solution itself? And how can you find the moles of the ions that makes up KHP?