Having just spend 2 days there on a stopover there and back from the UK, my food recommendation would be for chilli crab and black pepper crab, both national dishes as far as I'm concerned. Try
Jumbo on the East Coast Parkway - it's by the sea and gives you a good view and a refreshing breeze.
An alternative eating spot is Dempsey Hill, which used to be army barracks but now houses shops, bars and restaurants.
Another vote for Little India - do some shopping at the huge Mustafa centre
The zoo is meant to be good although we didn't make it there.
Taxis were surprisingly cheap ($20 to the airport) so we used them a lot to get around.