Alright i know a way to modify TX power in Linux but i don't think that's even possible on Windows 8.1 because of many limitations. I had the same problem when tried to change TX power of my wireless card in latest version of Kali. so here is what you need to do to up your TX power to 33dBm or even more.
okay here we go
first, if you're using Kali Linux ver 1.10, you will have to install 2 separate packages from the Kali repository.
apt-get install libnl-dev
apt-get install libgcrypt11-dev
you need to download these two files and put them on your Desktop Wireless-regdb and CRDA
extract each file into a folder with their name, since Kali ver 1.10 has a build-in Archive viewer, you can simply do it by drag-drop or alternatively if you want to use terminal, here is the command
tar xvjf
in this step after you've extracted all files to their folders, go to the Wireless-regdb folder and right click and open up a terminal
nano db.txt
this will open the db.txt and you can edit it to your needs. you will notice the country 00, it is the world regulatory domain and that is applied before everything else so in this case you will have to replace those values with the ones for BO country. do that and then you can change (20) to anything you want like (30) or (33). if you want to use 5.8Ghz channel, change both values. 33 dBm gives you 2W so i assume you know what that means.
- go back to Wireless-regdb directory and do "Make" in there. this will create some additional files including regulatory.bin that we need.
- copy the regulatory.bin file to /lib/crda directory and replace it but if you want you can backup the original file before replacement.
- Go to /lib/crda/pubkeys and copy benh@debian.org.key.pub.pem to /Desktop/crda-1.1.3/pubkeys/benh@debian.org.key.pub.pem
- exit the folder and go back to Wireless-regdb folder on your desktop and find all files with extension of (.pem), copy them all and paste them into crda-1.1.3/pubkeys folder on your desktop.
now it's the last step, go back to your crda-1.1.3 folder in terminal and type these commands
make
make install
after that restart your computer and do an iwconfig and you'll see your new TX power. if after restart the changes didn't take effect do a make install in Wireless-regdb directory too but i don't think that would be necessary at all.