8500 PLN net a month is about 30000 USD gross a year. Hardly tempting for a senior business analyst. Street sweepers make that in the richer areas of the US.
That's 4500 PLN right there. That will leave you with only 4000 PLN to support a family of three. A one-bedroom apartment will cost you anywhere from 1800 to 2500 PLN all inclusive. Leaving less than 2000 for food, entertainment and sundry expenses. Food and baby supplies alone will eat up almost all of that, leaving you with practically nothing left over for comfort or fun. If you are paying your own travel to Poland, you will have to deduct that as well, together with the costs of your visas and residence permits. That means you will lose out or only be able to save up a small amount toward your mortgage.
For you, it will be like living as a student. For your wife, it will be like going to jail. She will go crazy with nothing to do besides take care of the baby, fix your meals, and wash your dirty socks and underwear. She will certainly not be able to find work, and probably not be able to meet anyone to socialize with. There are very few Indian women in Poland, and they do not associate with each other unless they happen to be of the same class/caste/clan, which doesn't happen very often. Unless she speaks very good English and is a very assertive, outgoing and persistent person, she will not be able to socialize with Poles. If she is shy or reserved, she will be very, very lonely. Do you really think she will last long under such circumstances?
The problems with living in Poland for you are 1) very low wages (a third or a quarter of what you would make in the US or the richer European countries); 2) high cost of living relative to wages; 3) abysmal savings potential; 4) high travel/visa costs compared to wages; and 5) no Indian community for you or your wife to socialize in.
If you were coming alone, and leaving the wife to work and support herself and the child in India, you might just be able to do it, if you live like a monk on cabbage and potatoes. Especially if your employer is paying your travel costs to and from Poland. If not, you might even lose out on the deal having to send 4500 PLN a month to the bank back home.
No point in asking for more money. There are much better jobs to be had in the US and the richer countries of Western Europe, and probably India as well. I suggest you look elsewhere than Poland for a job if saving substantial amounts of money is a priority. And remember, the best jobs are practically always advertised solely by word of mouth, face to face, so network, network and network some more, aggressively and constantly. Recruiters and job websites get only the table scraps.