The view from her window shows us the Kowloon City branch of Hang Seng Bank and a quick glimpse through the window from inside the room reveals what looks to be the building next door to it.
If you look at the lower picture, through the window, it looks as though the camera captured the front of the building next door to the bank. Here is the Streetview of that section of road. Of course, I'm assuming the bank hasn't moved in 20 years...but the front of the next door building does look like the one on film.
Assuming I have guessed correctly, that would put the actual apartment in the building opposite - possibly the first floor of number 2B. Here is a quick grab of that building - I think the room is the one centre screen - but I'm open to counter offers :-).