You need to decide what your goals are. I would suggest aiming for a 10k race. you don't need to enter a race if you don't feel confident enough yet, but it sets you an achievable target.
You can either get a 10k training plan and maybe miss the first couple of weeks if it would be a step backwards for you, or you can write your own plan.
The gist of any plan is that you do a long run at the weekend and two shorter runs during the week. The long runs gradually get longer until your are running the full distance. So I would aim to do 2 x 30 min runs during the week (I guess that these are probably about 4-5k) and then increase you weekend run by either a maximum of 1k a week or 5 minutes a week.
Peachy is right that a club will help with motivation, particularly now that the nights are beginning to close in. Don't be afraid of clubs - you are certainly good enough for mine - and look for one that caters for beginners. Most club runners are people with a shared interest who want a bit of company on their runs, and the elite runners are the minority.
Well done, and keep up the good work!