How many times to repeat a set depends on your goals. After each set you should rest between 30 and 90 seconds depending on your intensity.

Here is a guide of how many sets you should do depending on your goals:
1-2 sets for general health, deconditioned individuals and beginners
3-4 sets for fitness, building muscle, fat burning, and intermediate to advanced individuals
5 to 6 sets for endurance, fat burning, and advanced bodybuilders

The number of reps that you do for each set also depends on your goals:
4-6 reps for strength and power
8-12 reps for building muscle
15-25 reps for endurance

What if you want all of it? Should you stick with one thing for a while,then shift your focus? Or should you alternate workouts weekly to target endurance one week and strength the next?

That's a good question. I think you can probably do it the way you said, but maybe you can also work on it first by building up your strength and then moving onto endurance. Not really sure though. When I think of endurance athletes, they aren't exactly the big body builder type looking people. And I don't see body builders having a lot of endurance so I'm not even sure it is possible!