Tourist Visa for H/K.

Good day,I am Nadishka Gunarathne Herath from Sri Lanka. My husband is a Singapore P.R. holder. My self and my two kids came to my husband and currently we are stay in Singapore as tourist. We want to go Hong Kong on my son's 1 st birth day. so my question is can we apply if we go to Singapore Hong Kong embassy or if we go to Singapore Sri Lankan embassy?
Thanks