As you are going to the court Monday morning, he should at least have a proposal at hand. For example, the child stays with you, he can visit (joint custody); he pays child support such such; he pays alimony such such. If he offers nothing, you have to consult a lawyer for your right. 4 months old baby needs to stay with mom. You need to survive. He can treat it as paying a most reliable nanny + child expense (food + lodging). If he wants the child staying with him, you can require not letting the child leave the country; which will cost him a lot. For the same token, he can ask you not sending child back China.
BTW, if say, he pays for a nanny (or daycare cost), can you go out to work and support yourself?