It's neither a hardware nor a software problem, but a regulatory one. Before you start digging around the settings of your computer or router, speak to the local agency regulating frequency concessions where you live and talk them into either extending the ISM allocation to the full ITU suggestion or obtain your own license for use of the 2483.5 to 2500.0 MHz band.
Alternately, I suppose you could argue that what you want to do is either a medical implant or a mobile satellite reception terminal, which is what the band is used for in most of Europe. I'm not certain of the power requirements for satellite terminals, but if you decide to implant the laptop (or router) in your thigh for medical purposes you'll have to reduce the mean transmitted power to a hundredth of what's common for 802.11 devices. I'm told capacity on experimental rocket launches is sometimes made available to universities, you might want to look into scoring some of that if you go for the mobile satellite service idea.
While I don't read Hungarian and don't know how to check if there have been revisions to this, ITU Reolution 9, annex 2 is a frequency plan for Hungary. if you look at page 47 in the second column from the right, you will see the 2400 - 2483.5 MHz band is made available under 7 different use cases (I didn't look them up in particular, but see above), while the band from 2483.5 - 2500 MHz is available for two of the same and one additional use.