While it certainly helps to take up a course in IP, however, it's not necessary to have the same for being a Patent Agent.
To become a patent agent, you need to apply for the Exam when notified by The Patent Office
You need to study:
# The Patent Act, Patent Draft Manual (both available free to download from Patent Office website)
# Practice drafting of patents and agreements (you may find samples available over the net)
# Solve previous years' question papers to get acquainted with the question patterns (question papers are also available free to download from Patent Office Website