I tried to post this morning, but the site was down. Anna, I've dug around for in town quick printing and don't know if photo/digital printing can be done in time for Monday, but here is a couple things that may help.
no full color or digital on corrugated plastic, but they do have 2-3 color. Start at about $30
153 W. 27th Street
Have lots of options. Best to call. May have to pay for expedited service which can double usual prices. These people have been on my 'to try' list for a while, but I have not yet used them...
Grand Photo Solutions/GPS
42 W 17th Steet
I use them for photograph printing. very good. cheaper than duggal. I don't think they print signs, but they will laminate your 11x17 print for $4. That may be an alternative.
CEC Artslink presents Publicly Creative: A Public Art Workshop. Public art is a fast-growing discipline with many unexplored opportunities for artists and communities. This workshop is a hands-on intensive introduction to the field, outlining resources, logistics, opportunities, and examples of successful collaborations. Recognizing artistic initiative as a valuable asset and a catalyst for a dialogue and transformation, we will explore how site-specific collaborations in varied cultural, geographic and political areas can influence business, social awareness and economic development. Encouraging close inspection of the particular issues faced by a specific New York community chosen by the participants, the workshop and the resulting public art work(s) will provide a unique platform for the participants and the public to explore and appropriate the city’s landscapes.