Cost of living in Singapore is very high.. In fact it has skyrocketed in the past 4 to 5 years.
Sai Surya was correct in providing the details. To add
Cost of one bedroom apartment - $1800 per month
Groceries,cooking etc - $150 to $170 per month.
I am assuming you use public transport for travel as its cheap and easy to use also.
Transport - $200 per month(2 persons)
Misc - $300 to $500 per month (going out,movies etc etc..)
So overall you can expect your monthly expenses to be around $2500 per month atleast.
Also, you need to pay the tax on your salary. So for a salary of $4500 per month, i can save upto $2000 per month which is equivalent to 80,000 INR
Regarding the salary for 8+ years exp - i dont know why its very less, i have heard one of my friends who is also in Java
with 7 years of exp earning $6500
per month in Singapore