You should be ask 印印 to renew the passport first, after when you renew her contract, the immigration dept will give her two year of visa, otherwise they will give her the visa expiry date = her passport expiry date (i.e. 年中). Then 印印 need to go to China a day trip and return to Hong Kong to extend the visa.
My 印印 is renew her passport by herself, it need two week of processing time, 印印 will know the proceduce, it is very easy.