Heart Failure Pomeranian?

Please if you do not know about this topic do not try to guess at an answer there is a life at risk. I am asking only medically trained or someone who had a dog with this issue people answer this question. I just found out today that my beloved pomeranian of 8 years is showing signs of heart disease. The vet said he heard a murmur and when they xrayed her her heart was slightly enlarged. He said it should have been only two something when her heart was a three. He said not to worry about it right now but monitor her closely and if things take a turn for the worse we can find a cardiologist for her. I'm sorry but that is not good enough. She is my entire world and I want to take preventative measures or do something I just can't wait for her to get worse. Is there anyone with suggestions or insight who can help us? She is 8 years old. She grew up on Kibbles and bits till I learned better and within the past few years we switched to all sorts of foods before settling on raw. She was a little bit heavier than she should have been but now her weight is down to a good size. Please ask if you need more information and share any advice you can.