How do I convince and make the judge agree on my offer of installments

I had taken some money from a friend to upgrade my business and the agreement was co-signed by a guarantor. I have made almost 40% of the payment but due to business failure I was unable to make the balance payment for a period of 6 months. After this 6 months of no income I found a job in a pvt company and my only source of income is my salary. I offered to pay him monthly upto an amt of 10000 pm & wrap up d due within a year and half but he is not interested. He demands that either I pay him d full amt at once or he shall sue me. What do I do? I have no ancestral wealth nor savings.