Where can I find a replacement spring, for usb port cover?

I left my MP3 player plugged into the usb port for too long. This resulted in my door loosing it's "spring" and would not return to the closed position. I have finally taking the time to look at what happened and I don't have the original spring anymore.

I need to know if i can simply go to any hardwear store and request a spring of that sizing, or is it something I need to find online(unfortunatly I did not see it on ifixit.com). If it is possible, I would be willing to make my own, but just don't know which material(s) would work best.

Thanks for your time :)