If you do a Google search for practice tests you can find some such as this site: CompTIA A+ Practice Test: Free A+ Practice Exams
Also, as Darician said, do everything you can to take the test this month. Starting the 1st of the year, you'll have to re certify every 3 years.
The last A+ test I took was in 2008 and it covered mostly XP and had several questions on some of the older systems. It basically covers a wide spectrum, everything from Printer errors, general installation and configuring of parts, to customer service care (how to respond to someone in a polite courteous way). Just having well rounded in knowledge in computer troubleshooting will help you out a lot.