i can't confirm with u, but queensway shopping centre sells loads of running shoes. with 9 new balance retailers located there, u stand quite a high chance.
or, u can always check out their factory outlets:
The Comtech
60, Alexandra Terrace, #02-09 Lobby B
Singapore 118502
Tel/Fax: +65 6273 1255
Operating Hrs: 12noon – 6pm (Tues – Fri)
except Public Holidays
IMM Building
2 Jurong East Street 21 #02-38
Singapore 609601
Tel/Fax: +65 6563 2026
Operating Hrs: 11am – 9:30pm (Mon – Sun)