Erres radio RA 616 speaker

I do have found this radio on my loft.
it has been there for over 40 years.
After puting a new cord on it and some careful cleaning with air and renewing the fus it did work.
That is great to hear the musick coming out of this radio.
unfortunately only one speaker is working.
Who can help me how to find a new speaker for this radio?
It is an oval speaker ~210x140 mm 
I do not know the impedance nor the power.
pieter