Vehadrah

Hello all! I am doing some minor repairs on my ES300 basically the only things that needs to be done is to replace the trim that is around the door and seals up the windows (Leaky). The only thing is that I am not sure where to buy this trim. Would I have to go to the dealership or can I buy it from somewhere else? Does it have a part #, serial # or manufacturer # that I can look up or use? Any info will help greatly!