If I would want to do the one workout continuously, then I would add a set, then another before start over by increasing the weight and decreasing sets back to 3. That way one work on endurance and strength in an alternating system.
It's the principle at the heart of progressive overload. You perform a little harder than you did last time.
Most people would do the same workout with heavier weights (as you've suggested), while others would add sets first (to 4, then 5 and so on), and after completing all the allotted sets, increasing the weights.