I am going to repeat this - do not use other software. I am not saying that all of them are bad, some of them maybe can decrypt this but they will shove unnecessary software / purchases down your throat.
To use the decrypter made by me, download the source code from here. Extract the zip file in which you should find three files:
1. Decypter.exe
2. privateKey.yashma
3. publicKey.yashma
You have to make sure that these three files are in the same directory with the exact same filename (except the numbering / do not double the extension)
Then just run Decrypter.exe and you should be free
P.S. Sorry if you got infected