Work / Salary for a senior software engineer in Poland [195]

Hi, i'm from India, and have 4+ years of experience in IT. I have been offered a job in Gdansk with 6500zl gross. Also one way flight to Poland as a relocation package. As I understand, its not great amount considering I'm getting well paid in India at the moment. Is it a good amount to survive in Gdansk, as I read the cost of living in Gdansk is cheaper compared to other cities in Poland. Also, It would be great if someone can give an average time it takes for a company to get the work permit.