Parts from a Pressure Cooker or an actual Pressure Cooker?
You can get a Pressure Cooker at the following locations:
At the Cap Counterfeiting Shack. Inside Fields' Shack. Located inside a small wooden box by the oven. The Nipton General Store, near the front entrance. There are five of them in the Ultra-Luxe kitchen. At REPCONN Headquarters, second floor, in the collapsed room. In Goodsprings, in Doc Mitchell's house, a settler's house, and for purchase from the General Store. On a shelf in the kitchen of the Presidential Suite of the Lucky 38. On the cooker in Jeannie May Crawford's house in Novac, although you will lose karma for stealing this item. At Vault 21 in The Strip, sold by Sarah. In the Silver Peak Mine Shack, in a sunset sasparilla crate in between the two small tables. Pressure cookers can also be found in many abandoned shacks, ransacked caravans, or sometimes amongst piles of junk.
I got the list from, http://fallout.wikia.com/wiki/Pressure_cooker#Locations_-_New_Vegas
"It's you Americans. There's something about nipples you hate. If this were Germany, we'd be romping around naked on the stage here." - Peter Molyneux