Samurott is a new water type pokemon in Pokemon Black and White. Samurott evolves from a Dewott at level 36, which evolves from an Oshawott at level 17.
Samurott is only attainable from evolving the starter pokemon Oshawott into Dewott, and then into Samurott, none of which can not be caught in the wild.
If you want all three starter pokemon and their evolutions, you’ll need to get to the first pokemon center where you can trade pokemon. Trade your starter, then restart your game. Do this process twice picking different pokemon. On your third restart, have all of your starter pokemon traded back and you’ll have all three starter pokemon.
