just saw this thread now so it's probably too late.
singapore old hands don't buy [original] dvd/blu-ray discs locally, unless there's a very significant closeout sale. places like hmv are just too overpriced (with ang moh expat packages and prime rents to pay, their overhead is just too high!).
the way to go is amazon.com (yup, the states). the selection is superb, standard international shipping takes just 2 weeks (shortest ever for me was 8 days), and the shipped prices are lower than in singapore shops.
obviously, no instant gratification, but hey, one can't have it all. hope this helps.