Short answer:
You can’t from that code
Longer answer:
So the code above will simply increment a counter based on the last value the counter was on. There’s no way to tell when that page-view or count starts from it’s simply a number. You have no data on when that page view was counted or even last updated and certainly not how many of those counts occurred in the last week.
I’ve written about this before as it’s not a simple topic but in a nutshell counting post views efficiently is a nightmare – by recording views and writing data back to that same data source you are removing your read-cache from the database query, every time a page is viewed your database will need to be read from fresh as a write has just written your post-meta value with a counter.
The most efficient way I’ve found of doing this is to use an external service like Google Analytics or Adobe Analytics then query their API periodically for your popularity data. Perhaps every 2 -3 or 6 – 12 hours (depending on your web traffic) and get your popularity data from a data source that already has it there. You’re really re-inventing the wheel with page-views – big companies have already spent 000s on making this efficient.
If you want to do it yourself – strap-in as you’ll be looking at multiple, separate database tables, custom indexing structure, cron-jobs to process lists of timestamps against pages and Ajax calls to your counter so server-side page caching can work effectively.
I’ve had to abandon the more popular page view counting plugins on the WP.org plugin repo as they were all dismally inefficient – adding overhead and page-load times that were unacceptable. If you’re running a small site it probably won’t matter – you should take something off the shelf and use that… but remember to add it to the top of the list to change when / if your site traffic grows.
Also, a warm welcome to WPSE @jimi-del don’t forget to read up on our community guidelines.