You spend 12-15 hours at work You spend 3 hours driving You didn't say how much you sleep, but I will assume you like your pillow as much as I do mine, so 8 hours...

.

that's a total of 23-26 hours per day. Congratulations, you have no life. Unless your work is your life, in which case let's roll with that.

First off really consider getting a place right next to work and right next to a gym, that way you can go to the gym after work instead of commuting for 3 hours... This is thinking strategically.

Let's pretend that work is fun for you and you are enjoying yourself all of that time (if you are not, it's time to re-evaluate your goals and figure out what you want in life).

Then the problem becomes simple, you love your life the way it is, but you know you need to get in some exercise. There is only two places to put excercise in the time your life allows, either during work or during your commute. During Sleep is out of the question.

The good news is there is one very effective exercise you can do while driving, it's called isometrics. you can also do this while in your cubicle. Basically you just sit there flexing your muscles. Nobody will even notice you are doing it. Flex your left leg 10 time, then your right 10 times, then your left arm, and so on, with your abs as well...

There is also some easy exercises you can do at work. You don't need an hour straight to work out. It takes me about 2 minutes to do:

10 hinu squats 10 pushups 10 sit-ups 5 pullups

That's only 2 minutes. If you are able to take a 2 minute break every hour while at work and do this, after only 10 hours of work you have done

100 hindu squats 100 pushups 100 sit-ups 50 pullups!

Combine that with sitting isometrics and you will be in better shape than most in no time.

Of course, you must practice this, you need to develop the habit. It's not going to be easy.

And if you are working so much that you have no personal relationships, you might be damaging your brain. I would talk it out with a licensed psychologist.

You say you already do push-ups and sit-ups. sounds like you just need to add a few more exercises to your routine plus some cardio. I like to do martial arts after sitting at my pc all day and it's a really great workout. I will go to the dojo because it helps me to be consistent and the instructors push you further. Sounds like this is not what you are interested in. However, martial arts have produced some of the fittest people in the world... For home training I recommend checking out http://www.akban.org/fitness/ There you can find exercises to round out your routine and also cool self defense techniques.