Maker's Row is a good start point, if you're ready for a small batch.
If you want prototypes I'd hit someone at Parson's or check out Coroflot:
From there find a D2M soft goods expert who can take your prototype, optimize it for manufacturing (simplify the sewing steps, pattern complexity etc.) and deliver ready to cut patterns. Then you just need to find a sew shop, you can hit SF / NYC or LA for domestic work at small batches then overseas when you're hitting larger quantities.