Jennifer, you could probably sell your accordion for $1200 or so, but you would probably not be able to duplicate the quality for the same money in today's market.
Hang on to that accordion. If you enjoy music and spend some time learning to play it, you will find that you can sneak a one or two hour "vacation" every now and then. Music can soothe, drive, and inspire. You have all the ingredients at your disposal.
Jennifer - I was sorry to hear about your personal situation. And your current leaky house. This box could be a therapeutic help for you but consider - you need the time. If you cannot see those spaces ahead in your life then pass it on. The cash could help with the house repairs and somebody will continue with the custody of the artwork. It sounds a delightful box and I'm sure there are folk on the forum already interested should you choose to sell.
The little money you might net between the sale of your Miller and buying something like a Regal wouldn't buy lunch for a week. Keep your accordion and see if there is some way you can raise the jingle without selling it.
I have a C and a D Bon Tee Cajun from Larry via a very good friend who sold them to me. Larry's boxes are really good accordions. My D is a screamer and the C has a big fat sound. Both play easily, unlike the ones I bought from Birdman and the Savoy that the Birdman "repaired" for me.