Limits will be based on three things, genetics, mental limits and training.

Genetics are a limiting factor you cannot overcome, a fact I have spent decades ignoring and managed to more than most would expect but I know in truth I haven’t overcome genetic limits.
The volume of muscle fibre types you have is genetic. If you are rammed full of red muscle fibres(slow twitch) you will have incredible stamina but limited explosive power, predominantly white fibres (fast twitch) power will come easy but you would burn out fast. If you happen to be a seriously lucky so and so and have masses of pink fibres which can be trained into either direction, most of us will hate you and you will be able to achieve either extreme. These fibres don’t do both but they can be made to work as if they were basically white or red cells with training.

Mental limits are there for good reason. Many have heard the story of the child getting stuck under a truck and the mother lifting the back end off as a passer by got the child out. A lift greater than anything done before or since by a human being when considering body weight. A totally untrained woman beating all comers in a one time lift. Sounds great, but in doing so she damaged most of her muscles, tendons, ligaments and a number of joints. She became chronically disabled and suffered daily pain, with no regret. What this tells us is the mind puts limits on what we can do for our own good. Without these we would destroy ourselves.
Flip side is that we need to be able to train our minds to accept being able to do things, as per my sign off. You say you can’t do what’s in the movies, I ask why not? You can’t start out as superman but you can start small and build up to it by believing in yourself.

Last but obviously not least, training. The greatest genetics and self confidence in the world means nothing if you don’t train.
If you want single punch or heave power you need to be in the 1 to 5 rep range and using compound movements. Your body needs to be working as a unit, not a series of individual bits and isolation doesn’t promote this.
There are some good workouts on here, I would advise looking at stuff by Goldfish, he is good on generics and our resident powerlifter so very well placed to help you here. An example is below
http://training.fitness.com/weight-t…rst-34522.html

In answer to your basic question there is no formula etc. to many variables. Just give it hell and if grappling is not your thing, use speed and punch kick combos to keep others out of grappling range, and of course learn some technique.