[bluebelldell]

and I don't know why....
I also don't know it's name but I have had it for perhaps a couple of years now with no problems until now.

I have posted pic and would really appreciate any advice on how I can (hopefully) save it.

[Margo]

It looks like a Ctenanthe. Or a Maranta. Commonly called the prayer plant as its leaves go up in the evening like praying hands.
It looks like erratic watering to me.

[Greengage]

I agree it Looks like a Ctenabnthe oppenheimiana tricolor (Never Never Plant). Check if the undersides are purple.,
Discoloured leaves is usually a sign of too much light especially direct sunlight. move it to a shady spot.
Roting stems too wet.
Curling leaves underwatering.
Leaf fall dry air increase humidity
Plants in this group require the folowingprotection from direct sunlight, high humidity ,protection from draughts and warmth in winter.
Oh and repotting every two years. that pot looks a bit buckled so it may need repoting and a bit of tlc. You could also try dividing iit in the spring.