I think you should sell your Janome and buy the Bernina. You should try selling your Janome I don't think you would get enough out of it on a trade in. (I sold Bernina machines) I always suggested different places to advertise free. There not a lot of dealers that have enough cash flow to give you what is fair for your machine.Truly there's not a better way to use the money evertime you sew you will remember what a nice gift she gave you.
Good Luck.