General Oraka, is sitting in the Presidium Commons, look on your map to find his location, the Salarian arms dealer is to the east when viewing map. The black arms dealer will send you looking for artifacts. Those are in the Kite's Nest cluster in the galaxy screen, more specifically you will go to Kite's Nest then travel through Harsa and into Vular, if the quest is active it should appear at the edge of the green circle.