Ms. Weng, you can't apply for it online or through an agent, your husband or you have to apply for it in person, For official document (such as Birth Certificate, Marriage Certificate, etc.) should be authenticated by the Department of Foreign Affairs of Philippines and finally authenticated by the Chinese Embassy.

for Chinese embassy in Manila, The processing time is 4 working days. It is 700 pesos per document for marriage authentication, In case of emergency, pay rush fee: next working day additional 1700 pesos, and third working day additional 1100 pesos.

The required documents:
authentication document: marriage certificate (original & copy),
your husband's passport
other documents required by the consular officer.