It depends on the volume/type of training you're doing. Are you continuing with the C25K program, or have you moved on to a more individualized training plan? As you become more accustomed to a weekly running routine, your time/pace should both see dramatic improvement.
I can definitely tell your motivation level, judging by your eagerness to get into races. Good for you!
So, it looks like in a 2-week period you improved your 5K time by 1 minute--did I do the math right? If so, then you're doing great! Think about it this way: a little over a month ago, you weren't running at all. Now, you're shaving minutes off your 5K time. Digest that for a second... you're totally a runner now!
I guess now we need to determine what your own expectations are for yourself in your goal race. If you have a time goal in mind, and your fitness level is high enough, you may want to extend the distance of your training runs--nothing makes a 3.1 miles seem easier than running 4 miles during training! Just be sure to listen to your body, and don't overwork yourself. Because you're new to running, even if you're running longer than the C25K program suggests, you should not run on the days it tells you not to. Because of your higher activity level, you can probably mix in some other kind of exercise on non-running days, such as core fitness or strength training. These can help improve your running form, which will also improve your times.