Please do look through the archives. One of the things I would recommend, if you have a budget of $1500, is a used model of a really good quilting machine. I bought a barely used Janome MC9700, for $800 off Craig's list, and it was a steal, not a deal! (List price on a new Janome MC9700 is $2,499!) And it's flawless, love it, love it, love it! But there are lots of other models that hold up excellently over the years that you should be able to get second hand for a reasonable price: Bernina, Babylock, Viking and others. Everyone has their favorite. That's why I suggested the archives.
Beware of inexpensive Brother machines. It seems there are two kinds of Brother machines. There are the expensive ones that are made of metal, and are awesome machines, and I'd buy one of those in a heartbeat. Then there are the inexpensive ones sold mostly in big box stores. They are inexpensive because they are made of plastic, built in third world nations, and not meant to last. I had one that died in 8 months. The repairs would have cost more than the machine originally cost me. I'm not knocking Brother. You have to do what you have to do to survive in today's marketplace. Even Janome has a cheap knock-off. Just be aware of quality issues. The Brother model you have is a lightweight, not meant to be a quilting machine. But gee, if you could get it fixed and working inexpensively enough, it'd work just great for piece work! And you'd have a back up machine. Perhaps you couldn't quilt on it, meaning quilt the "sandwich" (top, batting, backing), but you could still do piece work. I was without any machine for 4 months and almost went nuts! I'd have given everything to do piecework.
You can take your machine to a Brother dealer who does repairs and ask for a quote on repairs. Yes, it will cost you something to have them look at it, but you don't have to pay for repairs/cleaning unless you give the go-ahead. Just a thought.
Dealerships are also excellent places to look for second hand machines. They'll sell a new machine, and take an older one in as a trade in. They'll completely clean and repair the second hand machine before they sell it to you, and some places will offer a warranty of some sort. I didn't buy from a dealer, but I did "buy" a 5 year warranty from my local Janome dealer. For a set price, they will do all of the cleaning, repairs, and I had one-on-one classes to learn how to use my machine, plus I can attend all of the "in house" classes for free, and I get an automatic 10% off any purchases for the next 5 years, until the warranty runs out, or I renew it. I figured it out, and this warranty actually costs less than what it would cost me to have my machine routinely cleaned over the next 5 years, and the one-on-one classes were awesome, and I've been to several "in house" classes for free, good stuff too. So that was the Janome dealer here, but there are deals to be had at most sewing machine dealerships. Just make sure they have their own repair service.
I guess that's all I have to offer. Best of luck to you!