Suggestions needed: GPU upgrade

[Terryv]

I've recently acquired a cheap Alienware M17xR4 laptop

 

It's in fantasy condition and works great, but the GPU is pretty outdated (gtx 675m) and the most up to date Nvidia driver for this card doesn't support vulkan (on Linux)

 

I'd really like a more recent AMD card as it plays nicer with Linux than Nvidia does, but I'm not putting any option off the table.

 

Also I'd like to know where to buy some besides eBay, they seen very expensive there.

[Oalei]

What budget,country,psu, spec is there? 

[Terryv]

Canada, this laptop has a 240w power brick

 

I'd like to keep it under 400cad