Where's your lady from? I apologise for refuting some
suggestions listed above.
I would not recommend Food Republic. You could change
your reservation at Mezza9 to Straits Kitchen, which
is also in the
Grand Hyatt. It's a restaurant that serves hawker fare,
and it received a good review from Anthony
Bourdain.
There's only standing room at Wala Wala (Holland Village) and
Balaclava (at Suntec City and less laidback) whenever the live
bands play, but EIC and The UnXpected are very good. They play
popular adult rock hits.
If you don't mind rubbing shoulders with expats, Bluejade will
play at Muddy
Murphy's on the evening of the 24th, and they play similar
music. There's space to dance in that pub and the draught drinks
are very good.
Timbre
has 2 outlets. EIC play at the Arts House (Old Parliament
Building) outlet on Saturday evenings, and at The Substation on
Wednesdays. It's a laidback, open air watering hole at either
place.
I'm not a big fan of dance clubs, but I
didn't enjoy my experience at Cafe del Mar. Zouk is one of the
top-rated places though. And Ministry of Sound can't hold
a candle to that, but there are other watering holes in nearby
Clarke
Quay.
New Asia Bar is in the same hotel as Equinox, and if you want a
quieter setting, Ink Club Bar on the ground floor
has live music every night.
A visit to the Zoo and Night Safari (which are
side-by-side) is pretty much set in stone, but avoid the expensive
food joints there (unless it's KFC or Ben & Jerry's). The
three prominent museums - Asian
Civilisations Museum, National Museum of Singapore and Singapore
Art Museum - are highly recommended, as is the new Peranakan
Museum. Admission is free on Friday evenings.
If you're into walking tours, there are heritage
trails that take you through the Civic District, Katong,
Chinatown and Little India, among other places. I'm not sure if
there are guides anymore though.
I may add on some more later, but if all else fails, you
can always borrow Lonely Planet from the nearest
library. 
