I think that there are a few things you need to consider.
1) Exactly how old is your cpap. Iam not sure how much longer you could buy a cpap to go with the integrated humidifier that you picture as the M series is out and they do not work together. If your machine dies tomorrow you have a brand new dinasour humidifier.
Therefore if you choose to replace the humidifier maybe you should consider a stand alone. Many here seem to like the FP one. That way if your cpap dies in the future the humidifier will still be useful.
2) Consider used. If the machine dies, the humidifier may have lived on. Maybe someone here has a leftover tank model humidifier that you show. Ask? or auction?
3) I assume the whole unit is dead, not just the tank? Tank is $25 or so.
4) Do you WANT a new machine? Is yours auto or the base model? That would be up to you whether you want to spend the money and what you choose to buy.
5) How tight is your cash flow....?
All need to be considered. Maybe more questions someone else can add.