How far did you get into the game? I've never tried on your GPU, but what I can share may help in your situation:
1) When DS3 shipped I played start to finish on a 560Ti, below the min requirements.
2) In order to get it playable at all, I had to set everything to low/off (as you would expect), plus I had to edit my GraphicConfig.xml file and put in a custom resolution. The best I could do was 816x510, but it worked. You might have to go lower.
3) I'm not sure how far you got (if anything), but if you were in the very first area of the game and performance was beyond awful, don't throw in the towel just yet. For whatever reason, Cemetery of Ash was just killing low end NVidia GPU. Once I got out of it, performance was better. I mean it certainly won't blow you away, but it was good enough I could finish the game (base game anyway, this was way before DLC was around, so YMMV).
4) Someone made a low spec patch. Full disclosure: I've never heard of this patch (just learned of it today) and I've never used it. Here are the details:
https://ragnos1997.com/2016/09/09/dark-souls-3-low-specs-optimization-patch-lag-fix/
And a video of someone claiming to be running it on a GT720M, which is I believe lower spec than your GT650M:
https://www.youtube.com/watch?v=zw8jzrqNZDI
Again, I've never used it but if it's legit perhaps it would work for you.
25 fps in combat isn't half-bad for your GPU IMO... this game is much more demanding than DS2 (which was 60fps upscaled max everything on my 560Ti). With the above fixes it might get better. I wouldn't expect 60fps, I think I maxed out at 45-50 fps, but I never had that ragnos 1997 patch, maybe it will be better.