there isn't going to be a problem with the circuit breaker or any fuses, i can tell you this because one of the lights in the fixture is working. the popping noise that was heard by your sister, was from the filaments in the bulbs blowing due to excessive current. excessive current is cause by a short (in a short current and voltage go up, in a open current and voltage go down.)
i could go more in depth, and tell you why only one of your outlets still works on the fixture, but you said you have no knowledge of electricity, and wouldn't understand what i am saying when i tell you about how the lights are more than likely wired and blah, blah, blah.
you can call an electrician, and have them look at it and replace it for you, but they will charge you anywhere's from $30-45 per hour. what you should do is buy a new fixture (unless you want to pay to have someone fix it for you but you will probably spend the same amount if you just buy a new one) and replace it yourself. it is a simple process. make sure you shut off the breaker switch or pull the fuse before you start working on it, this will prevent you from getting shocked. there is only 120volts, but it will still give you a nice jolt. there should only be two wires that power to the entire fixture, you have AC power going to it, so there is no need to worry about polarity. disconnect the old one, reconnect the new one, test to make sure it works, and then remount the new fixture.
good luck bro. if you decide to do it yourself, and you have any questions, hit me up.