I assume that you mean the mass of Helium in grams, not amu's (That's just the mass on the periodic table - although, strictly speaking, to give the mass of Helium, you need to know the particular isotope of He)
If it is the mass in grams, just divide the mass from the P.T and divide by avogadro's number:
g/mole / atoms/mole = g/atom.
Please do not repeat your question over and over again. I make it a policy not to answer repeated questions or multiple questions.