This following is a function you could use to go to the right heading. You will need to pass in a string and the function will jump to the first heading that contains that string. The string can also be the heading number. Note I included a sub at the end to show how you might call the function.
Code:
Function GoToMyHeading(str As String)
Dim doc As Document
Dim vHeadings As Variant
Dim v As Variant
Dim i As Integer
Set doc = ActiveDocument
vHeadings = doc.GetCrossReferenceItems(wdRefTypeHeading)
i = 0
For Each v In vHeadings
i = i + 1
If InStr(v, str) > 0 Then
Selection.GoTo What:=wdGoToHeading, Which:=wdGoToAbsolute, Count:=i
Exit Function
End If
Next v
MsgBox "Couldn't find the heading containing: " & str
End Function
Sub GoToMyHeading_Test()
GoToMyHeading "3.2.1"
End Sub