Perhaps this will work cut and pasted., from your info, I looked up the weblink and rang the Transport co. 02-1344099. 1 trip daily, 9.00pm from the shuttle bus station, 454 bahts, 40 seats bus, 621 km, 9 hours ride. The bus is not very full for today (Tues 8.9.09) and tomorrow.this will help, here is a phone number.
Public Bus Service to other provinces. » Bus Number 389 - Suvarnabhumi Airport - Pattaya
» Bus Number 390 - Suvarnabhumi Airport - Talad Rong Kluea
» Bus Number 825 - Suvarnabhumi Airport - NongKhai