You can see the street signs seen on film are also on the Streetview capture as well as the 7-11 on the corner (which is the corner with Shanghai Street). The red/yellow one is for an estate agency called Hui Hing (惠興地産) and the red/white one in front provided the small clue to where this location was. The shop is called Kam Yuen Hardware shop (錦源五金). This area around Reclamation street is well known for its hardware stores (which all go by the title of 五金) so it didn't take long to narrow it down.
Anyway, as for the room used in the film, it looks like it was the first floor room of this dodgy looking place (the part with the pink paint job on the exterior wall) at 331 Reclamation Street.
In the film the room has been decorated to look like a love hotel but whether it is or not I have no idea. Given that Streetview was snapped after the film was made, the room seems to have been decorated just for the film but if anyone knows different please let me know - I really don't feel the urge to go and explore this one...