there's not many master students doing a pure stats degree at the university of Oslo, and as a consequence some courses are offered only periodically, but you can still "self-study" them for credits, and there anyways enough related courses in fields like computational finance, numerical analysis and machine learning.

https://www.uio.no/english/studies/mn-masters/modat-master/s...

regarding moving back to the US: you can always take a local job in the oil industry or perhaps in a global company like mckinsey and then move back when you have some real experience (it should be easy to get a job here)