Hey
Anjali_SHThanks for posting. There's a lot to think about here and I want to be really honest with you. Firstly, to address your most logistical question, if you were to be successful in applying to b-school, you will go through a background check process. They will verify if your entrepreneurial venture is real and they may even ask for tax records to prove revenue. So yes, if you are serious about this venture, I recommend making sure that it is a going concern. A letter of recommendation from a client may help, but I think you need to be ready for the background check.
Then, regarding not working while you are studying for the GMAT...not my favorite angle. It raises a red flag...if you can't work while you are studying for the GMAT, the AdCom will seriously question if you can handle the rigors of a competitive MBA program. I know it stinks but I recommend that you work full-time and study in the evenings/on weekends like the vast majority of other applicants.
Also, you mention studying for six months and that seems...like a bad strategy. My recommendation is to take the GMAT now and get a real score. Then you know what you are dealing with. Use that real score as your base to determine what you need to study. Study those items for 4 to 6 weeks. Take the exam again and see what happens. Hopefully, your score will go up. You can take the exam five times in a year and b-schools like to see multiple attempts.
Hope that helps a bit!
Krista