I was looking for co2 places and came across a home brew forum.
Try this place it should be nearer to you.
City Fire Equipment Company
733 Ridgedale Avenue, East Hanover NJ 07936
Phone: (973) 560-1600
Here's the thread if you want other suggestions, http://www.homebrewtalk.com/f35/co2-...24/index4.html
I went to SOS Gas in Kearny which is kind of near Newark but they seem to have different prices if you just walk in so you need to tell them you were quoted like $12 for a 5lb refill or you'd be charged $15-17.
From that thread there's some near Union where my tank is so I rather fill up around there and where the prices would be standard instead of that.