Amana fridge-freezer ice maker problem?

we have an Amana SRD522VE fridge freezer with built-in ice maker. It is now several years old and has given faithful service but a few days ago the ice maker seized up totally. Inspecting the ice tray, the base was more or less frozen solid and the metal stirrer (if that's what it's called) couldn't rotate. I therefore removed the tray, cleaned it out in hot water and emptied all the ice from it so it could rotate freely and put it back in place in the freezer compartment. 48 hours later still no sign of any ice appearing.
Any idea what I need to do. There is a little ice on the mechanism behind the ice tray ... should I just switch off, defrost and start again or is there something else I should try?