If you want to forward the mail with its text and a covering message then change as follows:

Sub AutoResponse(olItem As MailItem)
Dim olOutMail As Outlook.MailItem
Dim olInsp As Outlook.Inspector
Dim wdDoc As Object
Dim oRng As Object
Dim sText As String
Dim sSubject As String
Dim vText As Variant, vItem As Variant
Dim i As Long

    sText = olItem.Body
    vText = Split(sText, Chr(13))
    sSubject = ""
    For i = 1 To UBound(vText)
        If InStr(1, vText(i), "5.tour_booked : ") > 0 Then
            vItem = Split(vText(i), Chr(58))
            sSubject = sSubject & Trim(vItem(1))
        End If
        If InStr(1, vText(i), "5.tour_price : ") > 0 Then
            vItem = Split(vText(i), Chr(58))
            sSubject = sSubject & Chr(32) & Trim(vItem(1))
        End If
    Next i
    Set olOutMail = olItem.Forward
    With olOutMail
        .To = "someone@somewhere.com"        ' the recipient of the message
        .Subject = sSubject
        Set olInsp = .GetInspector
        Set wdDoc = olInsp.WordEditor
        Set oRng = wdDoc.Range(0, 0)
        oRng.Text = "This is the covering message"
        .Display        'Retain this line
        '.Send 'Restore after testing
    End With
lbl_Exit:
    Set olOutMail = Nothing
    Exit Sub
End Sub
If you want to send on the message exactly as it arrived but with a different subject then

Sub AutoResponse(olItem As MailItem)
Dim sText As String
Dim sSubject As String
Dim vText As Variant, vItem As Variant
Dim i As Long

    sText = olItem.Body
    vText = Split(sText, Chr(13))
    sSubject = ""
    For i = 1 To UBound(vText)
        If InStr(1, vText(i), "5.tour_booked : ") > 0 Then
            vItem = Split(vText(i), Chr(58))
            sSubject = sSubject & Trim(vItem(1))
        End If
        If InStr(1, vText(i), "5.tour_price : ") > 0 Then
            vItem = Split(vText(i), Chr(58))
            sSubject = sSubject & Chr(32) & Trim(vItem(1))
        End If
    Next i
    Set olOutMail = Application.CreateItem(olMailItem)
    With olOutMail
        .To = "someone@somewhere.com"        ' the recipient of the message
        .Subject = sSubject
        .BodyFormat = olItem.BodyFormat
        If .BodyFormat = olFormatHTML Then
            .HTMLBody = olItem.HTMLBody
        Else
            .Body = olItem.Body
        End If
        .Display        'change to '.Send after testing
    End With
lbl_Exit:
    Set olOutMail = Nothing
    Exit Sub
End Sub