You can order them online. I have had great success with swimoutlet.com. Their stuff is pretty reasonably priced.
Anyway, get yourself a parka and head out to the pool. It's really only chilly the first minute that you jump in. After that, the water can be downright comfy, and a lot warmer than a bike or run on a cold winter's day.
But here's the secret to the parka. After you hop out of the pool, run with your towel into the shower and rinse off all that chlorine. Then whip off your suit, zip up the parka and head home. Noone has to know you're commando, and you'll be warmer than you would be if you'd left your suit on.
Just be sure to drive straight home.