I'm unfamiliar with the Sony so all I can give you is the lowest common denominator:
Go into the setup and look for 'colour balance', 'RGB settings' or similiar. Then adjust the green to get rid of the tint.
Some manufacturers hide these settings and need a combination of button pressed to access them, others just offer two types of setup - service/advanced and standard/basic are usually used to describe them.
You should really be looking at your manual or trying to get hold of one. Hopefully somebody with some Sony experience can offer you more information.
Sounds to me like you've been the victim of another ebay scam, with the seller being economical with the truth in the hope of getting more money and more chance of a sale.
By looking round the internet I've found that particular sony model you have has a lamp life of 2000hrs.
Here's the number of lamps its used:
5650 / 2000 = 2.85 (2 lamps and 85% used on the 3rd)
With the figures you have given it seems that its gone through 2 bulbs and is now on its 3rd with another ~350hrs to go until it needs replacing or pops. Its almost certain that the bulb will be reaching the end of its life and could be causing the green push you see in the dark sceens
I hope you didn't pay too much because a new lamp will cost between £200-400. Not even sure if you will be able to get hold of a lamp for a projector thats over 4 years old.