Matthews pictures a gun which appears identical to yours and has the "AUTOMATIC PISTOL" marking. He says it was made by Santiago Salaberrin, of Ermua, Spain. (Ermua is in the Basque country of Spain; see www.ermua.es
for more information on the town). An identical gun was sold as the "Tisan" (apparently someone was already using "Titan"). The grips are not original; the original hard rubber grips probably broke and someone replaced them with plain wood. The Philips grip screw is also not original.
The honest truth is that the gun has almost no value on the market. If it has sentimental value, keep it for that, but don't spend any money on it. Those guns were generally of poor quality and materials, so I would have it checked out before firing. The caliber is 6.35mm or what we call .25 ACP; ammunition is available at almost any sporting goods store or gun shop.