Download a piece of software called xpadder.Connect your xbox360 controller and create a profile for bc2 and save it.Leave the profile open when you start up the game and you should be good to go.If you dont know how to create a profile you can download one, try googling bc2 xpadder profile download.You will also need to run xpadder in compatibility mode as it doesn't run with windows 7.
Like mentioned above you will get your ass handed to you, i have been a console gamer all my life and was really hard to swap to pc gaming with mouse and keyboard and used xpadder for a while but kept on getting pwned.I persisted with mouse and key and eventually got the hang of it( but i still get pwned

).