Use this http://gothere.sg/maps

Type in departure and arrival point, once at the result page, change the departure time and date and you will get the exact taxi fare (considering there is no heavy traffic of course, which almost never happens in Singapore anyway...).

MRT is very easy if you don't have a big bag to drag with you.

Just did a check and your incoming cab ride would be:

S$14.80

Way back to SIN:

S$29.58 (due to the talked about 50% surcharge for riding before 6AM).