Hi,
Miramar hotel is along havelock road.
To give a better idea, if u travel to zouk & instead of turning
left into Jiak Kim Street, u go straight. Then u will come to a
cross juction and u turn left. As u travel, you will see miramar
hotel on your right hand side, right beside Copthorne Kings
Hotel.
Not sure about the time, if i remembered correctly the buffet lunch
is from 11 am to 2.30pm. The name of the rest. is Orient Ocean. You
may want to call up and ask them to confirm the timing.
Hope the above helps. 
Cheers