Have you tried to reach out to local businesses? You could dedicate the area to a business that sponsored it and put their literature in your office. The dedication would be prominently displayed on a plaque in the picnic area and maybe one in the office.
I LOVE Angela's idea! I was going to suggest you ask your current vendors for $$ donation so you can buy the things you need but her idea is FANTASTIC!
Or have a car wash on the weekends! We have done that before