I would like to inquire the requirements in getting an employment visa and how much it will cost?

I would like to inquire the requirements in getting an employment visa and how much it will cost?Another thing is how long it will take?bBecause my husband's visa will expire on March 30.He is in china right now.Is there any suggestions if my husband could just possibly renew his visa in china?

Thank you very much for your usual and kind assistance