Amy is Peterson's PA and also his bit on the side. She seems submissive and quiet, putting up with his angry rants and misogynistic comments. It is all in the aid of a higher purpose though. Much like Krystle, Amy is on the hubby hunt! She wants to land herself a rich man to pay for her lifestyle. The problem with Peterson is that he's already married and doesn't seem to have any intention of leaving his wife.
No doubt, Amy knows most of Peterson's secrets. Does she know something about Rose though? After the stunt she pulled to discredit Adam Revel, it's safe to assume she won't be very forthcoming if she does have information.