When's the gig? If you have Prime Amazon can get it to you in 2 days or perhaps sooner if you want to pay out the ass in shipping costs.

My recommendation: call up all the local music stores that are LP dealers to see if they have replacement parts. If not, go to Home Depot and jury rig a temporary fix -- I'm thinking either a plastic tie pulled really tight, or a screw/nut long enough to fit. If you order online, you'll probably only have to use the temporary fix once before you have the real part delivered.