I did something similar to nink did. I had the questions sets loaded on my tilt phone. I did practice problems wherever I went. People usually read wsj in the bathroom, I was busy doing SC or CR. You will be amazed how many practice you can do a day! Do them while you ride the train/bus, go take a dump (i used to take serveral a day during work when i was prep), waiting in the line at mcdonalds, waiting in the line at the dentist, going to the gym, before I sleep (can't sleep), waiting my girlfriend to put on makeup, waiting my gf change while shopping. I think you can do 50 problems a day easily!
If you prep for 3 month, that 50x90=4500problems grand total minimum, and if you try harder you can easily do 80x90=7200 practice problems in 3 month without even putting any strain on your lifestyle.
I know your situation might be different than mine, but I think to quit your job to study for GMAT is a big mistake. The whole reason to get MBA is to get ahead at work, not quitting! You can do it, bro! Grind this out, you can see the light at the end of the tunnel!