My Best friend was taken from me

My beautiful dog, Soldier, ran off today and came back with what I thought was a BB gun wound.
My wife and I took him to the hospital to find out that it wasn't a BB gun but that he was shot by something (they don't know by what)
They informed us that they would need to do exploratory surgery to see if there was any vital organs hit or if it is in the gut.
Price for that is 2200-2500  
Please help, I don't want to lose my best friend.

UPDATE:  I lost my best friend, the shot was a lot worse than we anticipated. He died from his injuries.
We still need to pay for the unsuccessful surgery and cremation.  I am crushed and lost.