How do you get vibrato on the violin in one week?

Vibrato usually takes a bit to get down. If you want to start to improve your technique, first try doing long glisandos up and down the string. As you get more comfortable, speed up the glisando and your bow speed. It won't sound pretty at first, but it will improve over time. Start with your middle finger- it's the easiest to begin with.

Oh, and make sure you have your wrist in the proper position when holding the neck of the violin. A collapsed wrist makes it difficult to get the technique down. Also, don't grip the neck with your thumb- just let it pivot on the edge.