Thank you soo much both! It works like a charm with a revision implemented in code.

(with testing i found little mistake in revision - line num. 9):

varArr = xlFillvarArray(strWorkbook, strSheet)

should be just this, for combined codes to work:
varArr = xlFillArray(strWorkbook, strSheet)


So, for anybody else who might want to use this, there is combined code from vba masters in one piece :
Option Explicit 
Sub ColourValues()
     'Original by Graham Mayor. Modified by Greg Maxey
    Const strWorkbook As String = "C:\Users\skopa\Desktop\Předpisy a normy po oblastech.xlsm" 'Change to your path.
    Const strSheet As String = "Sheet1" 
    Dim varArr() As Variant
    Dim lngCols As Long
    Dim oRng As Range
    On Error Resume Next
    varArr = xlFillArray(strWorkbook, strSheet)
    For lngCols = 0 To UBound(varArr, 2)
        Set oRng = ActiveDocument.Range
        With oRng.Find
            .Text = varArr(0, lngCols) 'Change 0 to whatever your Excel colummn index is minus 1.
            With .Replacement
                .Font.ColorIndex = wdBlue
                .Text = "^&"
            End With
            .Execute Replace:=wdReplaceAll
        End With
    Next lngCols
lbl_Exit:
    Set oRng = Nothing
    Exit Sub
End Sub

 
Private Function xlFillArray(strWorkbook As String, _
    strRange As String) As Variant
     'Graham Mayor - http://www.gmayor.com - 24/09/2016
    Dim RS As Object
    Dim CN As Object
    Dim iRows As Long
     
    strRange = strRange & "$]" 'Use this to work with a named worksheet
     'strRange = strRange & "]" 'Use this to work with a named range
    Set CN = CreateObject("ADODB.Connection")
     
     'Set HDR=NO for no header row
    CN.Open ConnectionString:="Provider=Microsoft.ACE.OLEDB.12.0;" & _
    "Data Source=" & strWorkbook & ";" & _
    "Extended Properties=""Excel 12.0 Xml;HDR=YES"";"
     
    Set RS = CreateObject("ADODB.Recordset")
    RS.Open "SELECT * FROM [" & strRange, CN, 2, 1
     
    With RS
        .MoveLast
        iRows = .RecordCount
        .MoveFirst
    End With
    xlFillArray = RS.GetRows(iRows)
    If RS.State = 1 Then RS.Close
    Set RS = Nothing
    If CN.State = 1 Then CN.Close
    Set CN = Nothing
lbl_Exit:
    Exit Function
End Function