I guess if it is your first car, I'll make the suggestion that you go to your local auto parts store, Walmart, Sam's, Costco, (or whatever) and look up the correct replacement battery. Most batteries will last for 3-5 years in normal use.
Also, if you are new to this, the online TSRM trouble-shooting chart might be helpful:
http://www.cygnusx1.net/Supra/Librar....aspx?S=EM&P=4