Running

You can and probably should continue to slowly try to increase the total amount of easy km, like many have said, but I also believe you should incorporate some specific sessions to increase speed and strength. Just "run more" will only get you so far. These sessions should be a small percentage of the total amount of kms you're running weakly, but if you do them consistently you'll see results. These sessions can be fartleks and hill sprints. A sugestion for a fartlek you could be doing is 30s-60s fast, 60s very slow but not walking for 15-30 minutes total. Don't worry if you don't know how fast you should go yet, just go and do it and don't be afraid to get tired. In fact, please get tired, these are supposed to be hard workouts. You'll learn the paces with experience and by paying attention to your body.

Another thing: don't compare yourself to others or to what times the internet tells you are the averages. Also, you really can't compare... not even to yourself. You haven't raced yet. Training sessions can give you some insight, if you have enough experience, but they can never be a true test of your abilities, only a race can. You simply don't know what time you can do for 5km. "Don't race your training"

And a final thought, these sort of plans, couch to something, are good to get you moving. You've got that and that is fantastic and beautiful. Don't diminish that accomplishment. But now, at the end of the plan, it's time you begin to learn that you can suffer a lot more than what you think you can.