You can probably catch all you'd need in a short time almost anywhere you launch on the Rapp. Simply have a minnow trap (~$10) and some bait (that's the big discussion, bread, catfood, crushed crab, etc)
Throw the trap in around an edge (breakwater, pier, etc) while you're launching. And the minnows should be there shortly.
Barring that, you'll have to contact Bobby J of Mr Js Pleasure (on the board) as he'll know if there are any around Urbanna.