Saving Sampson

I have loved animals my entire life, so this weekend as we were driving home I saw a terrified dog darting in and out of traffic on highway 87, and i had to  pull over and try to help. The dog approached the car so I opened the door and asked if he wanted to go for a ride. He jumped over my lap and sat down in the passenger seat. We took him home and gave him a bath, some food and some much needed water. He is a very friendly dog and has great manners and I was hoping to quickly reunite him with his family. After having his microchip scanned, and the vets office making some phone calls, it seems like this poor guy was dumped. They told me it happens very frequently out in the country. I was heart broken. I have 2 large dogs already and I am unable to keep him. The local pit bull rescue told me that they could help place him in a home but only if he is neutered, heart-worm negative, and up-to-date on his vaccines. I looked in to the cost, and we will need about $250 to cover everything. This dog has stolen my heart and I can not bear to drop him off at a shelter. The first night he was with us, he cried and cried until I went downstairs and he climbed up in my lap and slept all night. He is good with my young children and just wants to be loved. Being able to get Sampson fixed up so he will be eligible to be fostered by the rescue is very important to my family. We are appreciative of any donation amount to help save this awesome dogs life.