Insert part of filename in Word VBA - vba

Question

I receive word ( .doc ) file names in this format -
MDouglas-DouglasM-02-01-2017-493058190498601
Wherein,
(1) " MDouglas-DouglasM- " remains static in the beginning of the name
(2) "02-01-2017" is the date, which keeps changing every day ( so next day it will be 02-02-2017, and so on
(3) finally, "-493058190498601", which again, keeps changing with every file.
I am only interested in the date "02-01-2017", which I want populated in the Word document at two places:
(1) in the body of the document, in place of typed "Month dd, yyyy",
(2), in the 2nd pg header of the document, in place of typed "Month dd, yyyy".
Again, the "Month dd, yyyy" is only typed twice in the document; one in the body and one in the 2nd pg header. And I want both places populated with the date in the expanded format, that is:
"February 1, 2017"
I could come up with the following macro:
Selection.HomeKey Unit:=wdStory
Selection.Fields.Add Range:=Selection.Range, Type:=wdFieldEmpty, _
text:="FILENAME "
Selection.TypeParagraph
However, this only populates the complete filename at the top of the document. Please suggest (in word VBA).

Answer 1

This will extract the date, others can do the code for the Range field swap (I'd be interested in how this is done)
Option Explicit
Sub Test()
Dim dtExtracted As Date
dtExtracted = ExtractDate("MDouglas-DouglasM-", "MDouglas-DouglasM-02-01-2017-493058190498601")
End Sub
Function ExtractDate(ByVal sPrefix As String, ByVal sFileName As String)
Dim lPrefixLen As Long
lPrefixLen = Len(sPrefix)
If Left$(sFileName, lPrefixLen) = sPrefix Then
Dim sRemainder As String
sRemainder = Mid$(sFileName, lPrefixLen + 1)
Dim vSplit As Variant
vSplit = VBA.Split(sRemainder, "-")
ReDim Preserve vSplit(0 To UBound(vSplit) - 1)
Dim sReJoin As String
sReJoin = VBA.Join(vSplit, "-")
If VBA.IsDate(sReJoin) Then
ExtractDate = CDate(sReJoin)
End If
End If
End Function