Help Hoover Get Well

My name is Hoover and I am a 4-year-old Rottweiler mix and I am currently not feeling very well.  My mom, Susan Smiley, took me to the vet last week and I was running a very high temperature and my leg was swollen. I had not been eating my dinner for a couple of days and was not feeling my usual happy self.
I spent four days in the emergency animal hospital where I was told I was a very good boy and the best patient ever. My fever is down but my leg is still very swollen and the skin looks funny and the doctors can't figure out why. They feel like I have something else going on in addition to the bacterial infection but are just not sure what. 
I know my mom spent a lot of money on me this weekend to help me get better and now the doctors are saying I need something called an XRAY as well as something called a CAT SCAN and a CULTURE taken and that is also going to cost a lot of money. I heard the doctor say I need these tests to find out if something "LIFE THREATENING" is making me feel sick.
 My mom and the doctors really want to find out what is wrong with me so that I can get better and go back to having fun with my fur brother Derek and fur sister Nellie and so that my mom won't be worried about me not eating enough or being a lot more laid back than usual.  My mom needs some help paying for my veternary costs right away so that I don't get sicker.
I know that my mom adopted me after her 18-year-old dog passed away and she always says how much I cheered her up and how happy I make her. My mom and everyone else always tells me that I am a "Sweet Boy" and I would be so thankful and appreciative if I could get well and continue to cuddle with my mom and make people happy.