Converting NESTED IF statement into vba code

I'm new to VBA code for excel and I am somewhat rusty on my back-end coding. I am currently having trouble converting this formula:

=IF(AND(J7>=12,K7>=1250,L7>=480),"Y","N")

This formula is drawing from three different columns. I am also trying to add this formula to every cell under column("Q"), "Q2" is where the formula is suppose to start working. The closest I have gotten is:

Sub Add_FmlFormula()    
    Range("Q2").Formula = "=IF(AND(G4>=12,H4>=1250,I4>=480),"Y","N")"    
    Range("Q2", "Q" & Cells(Rows.Count, 1).End(xlUp).Row).FillDown    
End Sub

If anyone can point me in the right direction, I would appreciate it.