Sub SetRange()

Dim rng As Range
Dim ash As Worksheet
Dim sRow1 As String
Dim sRow2 As String
Dim sRange As String
Dim sColumn1 As String
Dim sColumn2 As String

Set ash = ActiveSheet

sRow1 = ash.Range("G1").Value2
sColumn1 = "A"
sRow2 = ash.Range("G2").Value2
sColumn2 = "B"

sRange = sColumn1 & sRow1 & ":" & sColumn2 & sRow2

Set rng = ActiveSheet.Range(sRange)
Debug.Print rng.Address

End Sub