Abigail needs mass removed

We first heard of Abigail when were at Home Depot with our original dog Samantha...we were met by a guy who told us that it looked like we spoiled our dog...would we like another one...Abigail came to live with us about 6 months before we lost Samantha to a blood disorder..She was our Angel...now she is suffering from a tumor right in front of her heart and it is resting on her esophagus, making it hard for her to breathe ...we already had one growth removed from her shoulder.which was $800...but this is more life threatening and more expensive...anything to help save her is appreciated...we really don't want to lose her too.  Thank you