If Statement Referring To Another Worksheet

I am trying to insert an If statement using the

With Sheets("Sheet2").Select
Range("c" & rBegRow).Select
Application.CutCopyMode = False
ActiveCell.FormulaR1C1 = _
"=IF(Sheet1!R[-8]C[4]<>0,Sheet1!R[-8]C[4]*-1,Sheet1!R[-8]C[5]*-1)"
Range("C" & rBegRow).Select
Selection.Copy
Range(Selection, Selection.End(xlDown)).Select
ActiveSheet.Paste
End With

The reason is that once the formula is inserted in to the cell in worksheet 2 then I drag it down kind of like a copy paste so it changes automatically the if statement cell reference to worksheet 1 automatically. the trouble I am having is that I do not want to use the R[#]C[#] since when the contents of the information changes the formula does not work properly. If i substitute them for G9 instead of the R[-8]C[4] and H9 R[-8]C[5] but it inputs it in the actual excel worksheet as =IF(Sheet1!'G9<>0,Sheet1!'G9*-1,Sheet1!'H9*-1) therefore creating a value error.