My wife's St. Jude's Mechanical aortic valve is a noisy little sucker, indeed. I believe they installed an amplifier with it. I can easily hear it from across the kitchen table, above the fridge noise.
A while back I started a thread "White Noise Machine for Valve Clicking," you may find some advice there. I did buy a Brookstone white noise/radio/alarm for her, and it has helped alot on those difficult nights. Those nights are getting further and further apart, and they will for you, too. You are still healing and adjusting. Before long, this clicking will just be an important part of who you are. In the meantime, try a fan at night, or treat yourself to a white noise machine.