Creme Brulee did not set, can I fix?
I see several problems here. First, the recipe only has 3 yolks per cup of liquid, that's the bare minimum for thickening and does not produce a really thick custard like the one expected in creme brulee. Second, it is a stirred custard, not a baked one, which is a method for producing pourable or at least creamy custards, not "spadeable" ones where you can take out a piece with your spoon without the sides slowly flowing to partially fill the hole. Third, it does not give you a temperature, but suggests you to use time and a visual clue ("coats metal spoon") and that clue is also consistent with a liquid custard like creme anglaise, not a thick one like creme brulee. 

The best thing to do is to pick a different recipe for next time - one which uses more yolks and directs you to oven bake the custard in a water bath. Aim for 83-85 Celsius internal temperature (under 80 it will stay too soft, over 90 it will go grainy, so if you don't have a thermometer, it is very difficult to get it right). It will take several hours, that's normal. 

For this batch, I wouldn't bother reprocessing it in any way. It is edible as it is, use it in whatever calls for a custard sauce. It's easiest and ensures that you won't run into additional trouble. 

If you really insist on trying to make creme brulee out of this one batch, add more yolks and bake in the oven in a water bath until proper internal temperature.