Korea - Arriving in Seoul, Korea at 9:45 PM, how to get to Gangnam?

Next week I'm flying to ICN and my flight lands at 9:45 PM. The last limobus leaves at 10:00 PM. By the time I get out of customs, I'll miss the bus for sure. Other than the limobus, is there way to Gangnam after 10:00 PM? As anyone taken the taxi to Gangnam to know the fare amount?

Still taxi is very expensive. Even after 10PM, there are some schedules available.

http://www.airport.kr/airport/traffic/bus/busList.iia?flag=E
http://www.airport.kr/iiacms/pageWork.iia?_scode=C1203010200&fake=1285334449919

In addition to this, KE and OZ has a couple of 11pm-midnight arrivals, and they arrange buses to downtown. Oh, that is also included in the second link.

credit goes to bobbybrown for sharing this on Korean Air Forum. But above is the answer to my question to share.