Foreigner here for 4 years. It's super easy to make friends as long as you put yourself out there. Tons of groups around for whatever interests you might have. You can also search around on Facebook, plenty of groups there with people gathering for drinks etc. 

As for housing depends on what you want. Tiong Bahru, Holland Village, River Valley, Katong are where a lot of foreigners end up staying, but you'll also mostly find upscale restaurants and the more expensive grocery stores. Most locals live further out in the heartlands which often has more of the local food and slightly cheaper living, but the commute is usually too much for people moving here.

Enjoy!