What you need is a magazine, and you can find them at gun shops and gun shows, or, if you want to skip all of that, you can order them from a number of websites, including (but not limited to) Ammo Land, J&G Sales, Gun Broker, Auction Arms, Midway USA, Guns America, and from the Ruger website, among others.
The brand is Sturm, Ruger, not Strum- and we cannot tell without a serial number, However, if you visit the Ruger website, look under customer service, historical data, pistol, you can find your model, and the serial number range for year of manufacture.
Impossible to answer without a detailed description and pictures.
50-260 USD
100-500 or so
150 USD
325 or so
50-500 depending on specifics
Right side of the frame, directly below the cylinder.
See related link at the bottom for a directory of Ruger corporate offices.
It is Sturm, not Strum. A Ruger Security Six is about $300-$350 for excellent condition. Price will vary depending on stainless/ blue, and condition.
Strum Ruger has been in business since 1949 and is the only full-line makers of American-made firearms. In the results of the first quarter reports, Strum Ruger exceeded expectations.
Ruger has extensive sn on their web site. Value will depend on the condition, accessories, box, papers, etc..