Unfortunately the Git source I linked to is only for the core libraries and command-line utilities. The Windows GUI source code is not yet released. Apparently they're deciding on which license to use, and are pointing people to the (now expired) Win32 installer for version 1.24.
HOWEVER I was able to disassemble the executable, find the date check, and make a 1-byte patch to make it expire in 2047. I've uploaded the patched PokerStove.exe to my Dropbox account, the link is below. Just replace your existing PokerStove.exe in your PokerStove install directory (you may want to rename the old one to back it up). Should you ever reinstall with the installer, you'll have to copy this over again.
https://dl.dropboxusercontent.com/u/55558954/PokerStove.exe