Politely say that now that you have other duties/obligations that require your time and that quilting full time was not something you had in mind at this time.
I am afraid she will start bringing you the neighbors quilts, the church ladies quilts..etc...etc..you can not buy the batting, thread, etc for $20...and you need to stop this now before it puts you in the poor house...
Being nice won't buy batting or other supplies..let alone get the repair man to fix your machine that you are actually using for MORE than it was designed for!