not a bad working code! Are you thinking on implementing multi threading? I know this is not comparable with GPU but its not bad at all

Congrats!
I already have a multicore version somewhere on my profile. Solves up to Puzzle 50.
Here for example:
https://bitcointalk.org/index.php?topic=1306983.msg62884789#msg62884789But I won't give you false hope that this script can solve anything above 50. It's simply beyond the reach of python's capabilities.
You have to program in C++ yourself if the current scripts do not meet your needs.
