Zeus has an aggressive tumor & needs surgery

Our beloved 8 year old dog was recently diagnosed with a highly aggressive tumor in his leg. The only chance he may have is for amputation of the limb. We have exhausted all of our funds battling cancer with our other dog who passed on May 7, 2008. We are trying to raise funds for the surgery which would require a pre-operative MRI ($2000). The surgery is going to cost $2500. Any help is greatly appreciated at this point. We don't know where else to turn. Thank you for your consideration with helping Zeus.