First off...Welcome to the hobby and the forum here.
After a little Google search I came up with this.
They make a few others as well. Details list it using a standard 540 size motor, and a 7.2 volt battery. Most likely has a standard Tamiya style plug on it.
Others they make.
Did this come with a charger? Most likely a wall-charger? If it did, all you will need is a battery, if not you will need a charger as well.
I would try looking for a local hobby shop in your area. They should be able to get you up and running. You may be able to find something at Radio Shack as well.
I assume this is your first rc car?
Here is good first battery and charger if you need go shop online.
These would be a nice cheap and goof proof way to see if you like the hobby and would like to later on get something better.
Of course your local hobby shop should have similar stuff as well.
If you have any other questions, just ask. Myself or someone else should be able to help.