How much megabytes does Black Ops on PSN use?

Im getting a Playstation 3 soon, and the first game im getting will be Black Ops. Im gonna go online almost everyday weekday for 1-4 hours, im only gonna use my ps3 for Black Ops, and no other games. Im kinda a hardcore gamer, and I love cod :) So I was just wondering how much mb black ops online would take up per hour? Im on an internet plan thats 5gb a month im pretty sure, will that be enough? Please leave details about the download rate and stufff about Black ops.. thanks :D