Help me save Taavi and his heart!

5 years ago I went to the local cat shelter, to look for my first pet. It didn't take long before I found this grumpy grandpa looking cat, sitting on the counter, facing the wall. Taavi had been living in the shelter for a while, and did not like it at all. He didn't make eye contact, and stayed away from the other cats in the shelter.

I knew right away this was my cat.
I took him home, and we became best friends. He looked genuinely grateful for getting to leave the shelter.

A while ago, Taavi started behaving differently.
Getting aggressive against Sniff, my other cat.
Peeing where he was not supposed to.
Breathing heavily after chasing Sniff around.

I took Taavi to the vet and discovered that he has abnormal heart sounds. The vet directed me to another vet in town, that occasionally has heart ultrasound machines, maybe once every two months.
Today and tomorrow (19.8-20.8.2017) they surprisingly had the ultrasound available.
I called for an appointment, but of course there was none left.
Then after a few hours they called back with good news! Miraculously someone had cancelled their appointment, and taavi got a spot!
Well, taavi has no insurance, so this visit will not be cheap, and depending on what they find, it will get even more expensive.
Every penny counts.
I love Taavi more than anything. I want all the time I can get with him.
He has many years left to live , if his heart only allows it.