if it's not too late -
go to mitsuwa marketplace, which is located on 595 river road. the building backs up to the hudson river and as a result you'll have unobstructed views of the manhattan skyline. also, there's a good japanese food court, supermarket, and cafe inside the main building of the plaza. specifically, get the ramen at santouka, which is arguably the best in the entire nyc region.
http://www.mitsuwanj.com/en/index.htm
if you want a nice view of the skyline from an elevated spot, drive up the hill from mitsuwa into cliffside park. to get there, turn from river road onto archer st, then make a left onto edgewater road and go up the hill. at the top, you'll have a really dramatic view of the skyline.