Try The Sims 2 Graveyard, Sussi had a maid dress identical to your description.

http://sims2graveyard.com/download.html

In the last column of the list, go into 'Sussi's So Good Sims', then into 'Themes' and scroll right to the bottom to find 'Victorian'.
Download the top file 'MaidVictorian.rar' and the file beneath it, which should be the mesh:
'MESHSUSSIChGirlVictorian.rar'

If this isn't the correct mesh file, let me know and I'll find the right one.