Multiple options are available but all will require some serious relearning - which you may not have time to do amid study/exams.
One possibility - and I suspect it comes free with OSX as it does with Windoze - is one-handed Dvorak layout. It's apparently a remapping of the standard keyboard to one that is easier to use with one hand (both left and right versions are available).
Another is to find something in the way of keyboard mirroring software (only one I found was for left-hand use, sorry) that maps one half of the keyboard back onto the other when a specific key is pressed.
Another option is to learn how to type one-handed on a standard keyboard - http://www.aboutonehandtyping.com/howto.html
All of those options, as I said, would require some serious relearning - as would learning how to use a chorded keyboard.
It took me about four months to learn to touch-type in Dvorak layout (after years of hunting and pecking on QWERTY) and get up to my original speed - and I only managed that by changing both my home and work computer to Dvorak and forcing myself to use it. I also had a keyboard trainer program that I spent a great length of time on developing the muscle memory - as in I'd be on it between calls at work as well as running it at home.