help with amps

hi, could please somebody help me, im looking to buy 12v ac adapter for my fibre optic christmas tree as i have lost the original. I think i seen one on e-bay but the seller is asking what amp my tree is. I really dont know. how can i find this out... my tree is 5ft fibre optic with blue led lights on. thanks for any help...

There must be an inscription which comes with the product you have, which is called specifications. Look around for a sticker or something.
If still nothing is found, test the systems by using, say a cellphone charger output and feed it to your system. See if the LEDs turns on. That's for starters.

It might be having a halogen bulb illuminating the fibre part, can be around 10W at least for a 5ft tree. So I'd guess it can be using a PS unit of at least 1Amp rated at 12V(as you said).
Try it and reply back, but no guarantee as it's difficult to tell correctly on the vague info you provided