Bandwidth estimation question

I am trying to figure out if our hosting plan has enough bandwidth (currently at 15Mbps, our average webpage is 300kb). One of our members may win a peace prize for scientific work so there may be a media blitz. Does anyone know how much traffic a 'media blitz' (for lack of a better word) generates? I can bump it to 50Mbps but I am not even sure if that is enough. -- Thank You, Joe