I would suggest you first review the actual sword making process. As you probably, know real Japanese swords are composed of multiple layers of folded metals and these metals and the folding process varies depending on the sword maker. I'm not a sword smith but I have seen a master sword smith at work and I seriously doubt you will be able to harden the sword by just heating it. There are numerous steps involved and a skill set that, don't take this the wrong way, I don't think you have yet. You would probably just end up permanently ruining the sword. Collect all the information you can about your specific sword (manufacturer, date of manufacture, ID number, etc) and then contact the manufacturer to ask your questions.
BTW, is there a reason you thought there might be sword smiths on an anime site?
Edit - Fair enough. It wouldn't be the first time Y!A messed up. As for the sword. Since it's a mass produced model it's probably not been folded but stamped out by an industrial press. In addition, because this is such an inexpensive sword the carbon content might not be high enough to effectively harden and temper it. Sorry, I cannot give you a better answer, but here's a link to the heat characteristics of the type of metal you have if decide to go through with it. Good luck.