visa for china and hongkong for sri lankans

dear Sir/Madam,

Our daughter is studying in Tianjin Medical University, she is to be graduated in July 2013 and my wife and I wanted to take part on this occasion and wanted to travel to Hongkong for one week and come back to China mainland and fly back to Sri Lanka, we want to stay one month all together, my question is what type of visa do we need to apply and where? how much is the fees in Sri Lankan Rupees/ please answer asap.

Thanks