Molecular weight of NiMnGaFe compund problem

I have a big problems calculating molar/molecular etc masses, because in my case I have a monocrystal, co I cannot imagine it as a molecule and my compound is made of Ni-Mn-Ga-Fe. I know the mass and the atomic and the mass percents and I need to get molecular weight. 


In the atomic percents I have: 50% of Nickel, 25% of Manganese, 17,5% of Gallium and 7,5% of Iron. So the ratio (of number of atoms) is 2:1:0,7:0,3 and I can find the atomic masses of all these elements but what is going to be the molecular mass? 


I am sorry for probably trivial question (I am really dumb in this area unfortunately and I was searching on the internet for answers but every time the structure of molecule was known and this is a crystal)


