There are many different barrel options out there for you to choose and many have the potential to be accurate. I have a factory Ruger bull (.920) barrel for mine and it shoots 10 shot, .750 groups at 50 meters and I have a Lilja stainless barrel for the same rifle and it shoots .430 10 shot groups at 50 meters. You will need to have the original barrell channel opened up to fit or can aquire an aftermarket stock. As far as ammo is concerned testing different kinds in different barrels is the only true way to know if it shoots good, and stay away from the high velocity stuff it is very inaccurate from any barrel I have tried. I have a Fajen stock and am very happy with it. Here are some 10/22 pre-fit barrel manufacturers, Lilja, Shilen, Green Mountain, Butler Creek and these are some of the many. My faves are Lilja and Shilen but are very pricy ($500 +) GM's are more affordable and have been known to shoot well for the price, Butlers you get what you pay for. Here are some links to look at:
http://www.riflebarrels.com/products...le_barrels.htm
http://www.shilen.com/rugerBarrels.html
http://www.gmriflebarrel.com/catalog...iameterbarrels
http://www.butler-creek.com/products/barrels_blued.html
Happy shooting
P.S. The hardest thing usually is finding the right person to export it from the U.S. for you, but if you find what you like then ask around at gunstores and online.