well first ....and I am sure they have but have they talked to the local vets in the area to donate their time and surgeries...etc.?? They also might want to see if any attorneys will do pro-bueno for them as well.
We have a local no kill shelter here and they have a thrift store attached to the shelter that funds the shelter. We donate EVERYTHING to them!! I might suggest a large garage sale. Advertise it in the paper and ask ppl to bring things then advertise the sale itself. You will be surprised what ppl will give you and how much you can make.
Also you can go to your local Eagels or Masons club and ask them if you can do a charity dinner. Then have ppl make salads and spagetti to donate for the dinner...advertise it as a fundraiser for the no kill shelter and you would be surprised at how much $$ you can make at that as well with little to no overhead. You can ask a local school to provide entertainment ie. band, play etc.
Those are two things that come to mind right now...hope that gives you some ideas.