And since the prom is in December. Might as well you go
around to find out.
There is seamstresses at Tanjong Pagar Market/Hawker Centre,
they do fairly good work at creating chanel and gucci office wears,
but they are very busy, (You can see from their shop how busy
swamped they are.) And I doubt it will be within your
budget.
I prefer going to the seamstesses at City Plaza to make a brand
new garment.
Katong Shopping Centre has seamstresses and tailors too, and
they also have plenty of ready made garments they can alter to your
sizes. Though they are more traditional stuff like cheongsums
and sarong kebayas.
Chinatown MRT there, next to OG, also have a few floors of folks
selling cloth and seamstress/tailoring service, so you and your
friend should take some time walking thru there.
There is a 'Just' shop I think they sell gowns at Chinatown
Point. Maybe you should go take a look first, before you
decide on tailoring instead.
BTW, if you must tailor, and you are on a budget. Consider
tailoring a really ultra simple gown in a interesting fabric and
not a black colour. So the gown can be worn onto other
occasions.
I got a replica Vera Wang Denim Gown in dark denim blue, for
wearing to dinners, weddings & whatever event. Either
throw on a cowboy hat and boots for a theme company event, or a
simple pashmina shawl for a Raffles Hotel wedding dinner event.