Maybe you can get enough money from people who want feature improvements to keep the site up for a little longer. If you have some consistent users you must be doing something right, and it definitely looks like a well made website.
I'm one of the co-founders of BountySource and would be happy to answer any questions about our service. We're also on irc.freenode.net in #bountysource if you want to come chat!
You desperately need faceted search on that interface. Something like Apache Solr. Otherwise, it is very interesting to look through the projects.
I also don't know if all those 'joiners' icons add much, especially since many of them a blank github images. Social proof is great, but I would put something else in there instead. Something more action-causing.
Maybe you can get enough money from people who want feature improvements to keep the site up for a little longer. If you have some consistent users you must be doing something right, and it definitely looks like a well made website.