The Romans were greatly surprised and terrified by the elephants in the first part of the war,but eventually they figured out how to fight them (letting them through the ranks, isolating, then killing them). I can't recall how the Romans got their own supply; it may have been a combination of capture and their own trading (Macedonians as middle-men?). For a while after Hannibal's defeat the Romans continued to use war elephants, but eventually gave them up.
Livy and Polybius are great ancient sources for Punic War histories.
Today has not been a total loss! I learned something new about the Punic wars. I just watched “Alexander” last week and saw how his armies made contact with the Indians who riding their war elephants the Greeks. Looks like you paid a lot more attention in class than I did.