I don't think there's a VIP bus service to Bangkok, depends on what you mean by VIP.
The bus station past Market Village only serves Korat and Chiang Mai.
For Bangkok take the blue and white air-con bus service around corner from Night Market near the Boat restaurant.
Details here :
www.tourismhuahin.com/busses-huahin.php
There's also a green & white bus service (no air con)which is slower and the minibus van services.
Buses arrive at new Southern Bus station which is a bit far out but taxi rank there. 3 or 4 of the daily departures also stop at Mo Chit bus station which is a few minutes walk to Sky train Station.
Minibus goes to Victory Monument.
New airport train not fully operating yet to Makasan in BKK.