have you submitted application to ID for visa? If so, you may once obtained the VCA no from the agent, wrote to ID directly, quote the details of your maid including her vca no and your contact no and of course your reasons for a fast application. For my case, once I faxed the request letter to ID, they called me within a week, the visa was ready for collection in two weeks' time from the date I submitted the letter, so quick and I was very impressed. I asked the agent to go up and collect the visa and the maid arrived in HK two weeks later.
you may write a letter to the Immi. Dept requesting for an urgent processing of the documentation. Just tell them your grounds, e.g. both u and your husband have to work and you have nobody including the grandparents or whoever, to take care of your bb after you resume your work.
i heard that the ID would not entertain any request for urgent processing by agent, if it is not directed from the employer directly. so to show your sincerity, you either have to write to them or contact them directly to speed up the case.