Please help/suggest software solution

I am trying to edit an Autocad map converted to PDF to JPG to BMP. The map has office numbers, names and departments. I need the office numbers but want to replace the other info with jack numbers. I have tried various graphic editors to no avail. Currently I am using Paint the map is converted to a Bitmap. Our building is large and working with a Bitmap is tedious. I asked our PC and system admin group for suggestions, they have none.