First option would certainly to send it to you local Toshiba Service Point/Repair Center (or whatever they call them these days) and tell them what happened. They should know what to do!
Second option (I don't really suggest it, but if you wana take the risk then go ahead).
1-Put the laptop in an outdoor place (hopefully it is hot), not in direct sunlight though. A few hours just to evaporate any remaining water.
2-Find the manual and start unscrewing , then visual check any remaining water droplets.(Dont forget under the keyboard)
3-Remove the harddrive/harddisk, (Just to keep your data safe) -I strongly suggest backing up any vital data (I dunno maybe a harddisk to usb adapter or something would work)-
4-When you are sure that there is no more water, start it up (Thats the part that i say 'Good Luck'), if everything went on smooth (ie. No damage to the screen,motherboard,..etc) then attach your harddisk back!
I haven't tried it before and hopefully won't need to, but i had a similar situation with a mobile that took a dive in a swimming pool and i kinda did similar steps.(Used tissue paper and a hairdryer,low heat mode to speedup the drying.. I know it aint the smartest idea, but thats just me).
Well, ofcourse i would say Toshiba Support should have their own ways with dealing with such problems. Refer to the second option, if they said you'll have to trash it or something and you'r willing to take the risk.
Good luck,
knouh