I'd try e-gunpart.com or gunpartscorp.com.
how much?
Try e-gunparts.com, gun shops, gun shows, want ads, internet searches.
DO NOT FIRE until checked over by a competent gun smith.
i am also looking for this
Try on line auctions, want ads, for sale ads, egunparts.
Unlikely
egunparts, pawn shop, gun shop, gun show, want ad
If you don't have a manual, request one from the maker or find a gunsmith and ask for help.
You may be able to find a magazine for a Hawes 25 cal pistol through online gun parts retailers, auction websites, or by contacting gun shops that specialize in vintage firearms. Be sure to check availability and compatibility before making a purchase.
Titan brand .25 caliber handguns were made by Tanfoglio, an Italian gunmaker. They use proprietary magazines. Some other .25 caliber magazines from similar handguns may fit, but there is no recognized interchange and no guarantee that a mag that fits will feed correctly. Your best bet is to look for a Titan/Tanfoglio mag at a gun show or a used gun parts dealer like Numrich.
Tanfoglio of Italy.
Find a gunshop and ask for help