You should be able to buy the barrel from Ruger, it is not listed as a part that must be factory fitted as is the barrel on most Ruger pistols. Barrel is easy to install, held on with one bolt and lock washer.
You can't really buy parts from Rugar on line . If you call Customer Service I'm sure thet can supply one. I've called Rugar for repair parts . They want to make sure you get the right parts foryor gun, by ser.#. I've called for misc springs and they sent them at no charge.