Your BS in Civil should go into the differences. Civil Engineering is made up of several areas that some people specialize in(like traffic, geotechnical, environmental, etc). It is a good place to start your engineering studies and from there you can go business (MBA as mentioned by gtrainor) or one of the other specialities you mentioned, depending on your interests. This is a very debatable topic right now in the industry...some want to break away from the all incompasing CIVIL liscense and go to structual registration (SE1 and SE2), traffic (PTOE), even things like sedimentation. Others think that this takes away from the prestige of a Civil Engineering registration/liscence.
Think of the medical profession...internal medicine versus brain surgen. Both or PhDs, but at some point they went into specialty training all depending on their interest. What do you enjoy? Do you stop at construction sites and wish you could know what and how things are bieng done, do you wish that you could be directing the work force on the construction site, do you even stop at construction sites, what about interest in foundations or traffic signal timing settings? Remember that your BS is an introduction. If you really think that you have found your interest then go on to graduate level, if not then maybe some time working after college will help you decide.
One suggestion that I give the college interns that I hire is to find a summer internship and learn all that you can in the summer... what the engineer does on a daily and yearly basis. If they stick you shoveling ditches then quit and find another. Start your internship search early, cause you will not make the company any money (you do not know enough to contribute, or at least the last three interns that I hired didn't. I still hire them because I want to help them in their carrer), and not many positions are found, or few slots within the company. Also gain a relationship with some local engineers by asking them for input and visits to their office.
Knowledge in a potential hire is one thing, but ambition and desire far out-perform, and is a major thing I look for in interviews.
Good Luck and have fun