A modern Ryzen chip's integrated graphics will outperform your old gtx 650.
This is a tall order, if you want a real graphics card inside, but something like This (please don't just pick the exact linked one lol) would be an overall upgrade. There are a lot of "compact" "small form factor" PCs out there that companies have already built around a tiny case.
I also don't know what your budget is, but I assume you aren't looking for just a beefy laptop.
The power supply requirements is pretty easy, PC part picker actually has that info on it, where it will estimate the power consumption of a list of parts.
Oh yeah, you can find "workstation" Dell or Lenovo PCs on Craigslist and eBay for pretty cheap because they upgraded a whole office at a time. They often have solid processors and ram inside already, but no GPU.