I stayed at the Hilton on Orchard Rd a couple months ago. I went to the food court in the basement of ION Orchard (Food Opera) a bunch of times. It's a great place where you can get hawker dishes. It's open till 10pm except 11pm on Fri & Sat.

http://foodrepublic.com.sg/stores/ion-orchard

Tons of options. Had a couple of amazing dishes there. Then again, I am a complete novice when it comes to Singapore, and so I don't know how their food would compare to nearby hawker centres. Walking distance to the Hilton. <10min from the food court to your hotel room as long as you take the right route. You want to take the correct escalator up out of the food court and then be sure to continue down on the higher basement shopping level so that you cross Paterson Rd underground to get to the Hilton side of the road before you come up.

It's not just the Food Opera. On the same level as the Food Opera, but on the other side is a bunch more eateries and food shops. Had an amazing Singapore-style coffee there on the recommendation of another FTer.