This last trip had the pleasure of going with True Sportman and fellow CRTer (sorry forgot you handle) to this restaurante.
Exact location eludes me as I wasn't paying close attention but it is very close to the INS building. Mostly all tico clientele business people. The place has three sections; just keep weaving through to the back and it is muy tranquillo.
We each had one of the casados and all were excellent. I had the dorado a la plancha, very fresh and tasty! I think the pricing was around 2100 colones. Well worth it! (Especially since True Sportsman paid!!!).
Sorry the directions aren't better but worth the exploration
Pax,
Sluthog