Help with "Bru" Raymond surgery

My name is Shawn Raymond and with my girlfriend Michelle Healey and both of our families, we share Bru who is our baby. He is a 5 1/2 year old pure bread Boxer. On Saturday July 25th Bru collapsed in front of Michelle (his mom) and we rushed him to Walpole Tufts Vet Hospital.  After a few days there Bru was diagnosed with a cancer tumor in his intestine. It is the size of a golf ball right now. We were told he is in need of surgery as soon as possible, but it can cost between $3000.00 to $4000.00.  He is also anemic because of this so he is on medication to keep his heart beating regularly so he will not pass out again.  The staff at Walpole Tufts Hospital is wonderful and they explained that he is in need of this surgery within the next few weeks. 
I am a single father raising 3 kids through joint custody and my girlfriend is a single mom with 2 kids in college. We cannot come up with all the money at once. Without this surgery Bru could collapse again and possibly go into cardiac arrest and pass away. We have had Bru for 1 1/2 years now and he is our baby through and through and is just like our kid. We do not like asking for help but this is a dire situation and we need to do what ever we can for our baby. Bru is a loving, smart, caring and fantastic dog. He is loved by many of our family.  IF you are a pet loving person please believe us that this is a very hard thing for us to ask for help but with any help we can get for Bru, he will have this surgery and hopefully live a full life that he is meant to live. We need all the help we can get for our baby! Please help us help him.  Thank you from the bottom of our hearts!!