For starters, I'd try Ludlow Guitars for a Jag (not sure about the Squier, though). If not there, there's a few other shops I can't remember the name of in the same area of the Lower East Side. Here's a map:
http://maps.google.com/maps?oe=utf-8...ed=0CAsQnwIwAA
Basically, the square between Houston, Delancey, Allen, and Clinton (or even a bit further), are chock full of music stores, clubs, and other cool places. Just watch out for hipsters!