Cardiac issue?

This is kind of long to post here, but it is why I came to join.

We have a cat who we rescued who is about 10 yrs old. She is a beautiful long-haired calico. I don't think she was feral, as we had a cat previously from a kitten who was feral and she was wild all her life. She has been healthy and happy these past 10 yrs. She is a sweet girl and strictly indoors.

Last summer, she had an episode where her back legs stopped working. We took her to the vet. She had lots of blood work and an x-ray done. All was fine. The vet felt it must be a clot, but didn't think it was a serious cardiac issue since she didn't appear to have any pain. The only thing we did not do was go to the specialty vet for an MRI. She could move one leg slightly, but the other was dead.

We nursed her through this time. My dd worked her legs as the vet had showed us. Eventually, she was able to limp around and finally walked relatively normally. The vet told us if she regained use of her legs, we didn't have to return. She has been fine since. The dr felt it must have been a random clot and not the serious heart problem. Even if she never regained use of her legs, the vet did not see a reason to put her down. She said that she had never seen such perfect blood work in a cat before.

Now, recently, she has been doing some odd things. Nothing completely weird. Just strange. As long as we have had her, she has NEVER sat on the dining room table. However, the other day, I saw her sitting there. She has also taken to sitting on a low shelf below dh's desk in his home office. One day, she sat in a plastic bin with clothing inside for an entire day. She seems to go through days where she will stay essentially in one place the entire day. As soon as we worry, she will have a normal day. She also has tremors in one of her rear legs. Another odd thing is she is talking a lot. But she has not ever done this before.....only for food and water. She is a large cat as well. Some days she seems to eat less. Also, the final clue to me is we have heard her cough. Not on a regular basis. Just now and then....one day, and then a week or so later. Nothing I would think is serious. And some days she seems to have a hard time settling down. Oh....and now and then, she will poop on the floor. Her box is upstairs and I wonder if she is too tired to go up there at night. She goes up very slowly and I'm not sure if it is her leg still not up to par or weariness.

My dd, 17, who adores this cat, has even wondered aloud if her cat is going to die soon. She just acts strange.

I am not overly concerned, but I did do some searching and everything I see makes me wonder if she has CHF. The problem is, I don't think we could afford to buy her heart medications. This is what keeps me from taking her in. None of this seems to cause her pain...although she isn't fond of being held much anymore. I've told my other children to leave her alone so she will let dd hold her.

My only other thought is something degenerative which would again call for the MRI. We simply cannot afford an MRI. I think she said it would be over $1,000 just to see the dr!!!!

My fear is that if we can't afford medication and we take her in that the dr will want to put her down. I don't think my dd could handle that if she LOOKS fine right now. Some days she seems perfectly normal. But some days, I just wonder.....