Both other posters give you OK, albeit completely different, advice. However, I think one is too much focused on intensity (especially for the offseason) and the other is a little too focused on a magic mileage number. I personally think consistency is the most important thing, and honestly you probably don't need to do that much to make a lot of progress given your minimal training background.
I would recommend training about 5 times a week, something like this (you can change days around, but I would stick with 3 days on, 1 day off, 2 days on, 1 day off).
Monday: Off
Tuesday: 10min w-up, 15-20min of tempo work, 10min cooldown. You can divide the 15-20min up in any way you want, as long as you a repetition is at least 4min long. So 4-5x4min, or 5-4x5min or even 2x10min or a 15-20min tempo.
Wednesday: 30min easy run
Thursday: 10min w-up. Short intervals. Either 6-8x400m, 10-15x200m, or anything similar (total distance about 2-3km of tempo work, 1.5-2.5min recover between reps). If you have a nice hill close to you I would do a hill workout every other week, something like 5x1min + 5x30sec, with jog back rest.
Friday: Off
Saturday: 60min easy long run.
Sunday: 40min progressive run. Starting at an easy pace (8:30min/miles?) and slowly speeding up ending the last mile in about 6:20min/mile.
Do strides after your w-up on Tuesday and Thursday. 3-5 of them.
Every 3-4 weeks, depending on how you feel, you can add 5min to each run. So after 4 weeks: Tuesday's 20-25min tempo work total. Wednesday 35min run. Thursday about 2 repetitions more. Saturday 65min run. Sunday 45min progressive.
Also try to do some core stability after your runs.