if you're bored, you def need to change things up. Your body will get 'bored' too, and will plateau. Try simple things:
Run backward for intervals, sprint up short hills, pull a weighted sled (not sure if you're joking about being in S. Korea, but if so, is there such a thing as a grass field there? LOL
Get some info on plyometrics. Be careful and start slowly, some of this stuff can be hard on the joints of a newb, but it'll make you more explosive and is easy to add to a running routine.
Also, vary the duration of the workouts. To start, make 1 per week 1 hour long.
At least for me, I try to run outside whenever possible. You don't get bored NEARLY as fast as on a treadmill, and if you're happy, you'll get much more out of the workout.