We're pretty low on foam ourselves, sort of at that middle area where we have enough probably for this season, so we probably won't be making a trip to our usual supplier until the end of the year or maybe next year early on.
You can order the same stuff we use from Edhellen (
http://www.edhellen.com), and if you tell them you're from Riverbend they'll either give you a good deal or charge you an extra Brutus tax.
Another online alternative is a place called McMaster-Carr (or something along those lines). They will be much more expensive, but the foam is extremely high quality and lighter than the stuff we use, while being just as durable.
There isn't really any supplier of foam suitable for weaponry that I know of around these parts.