Patricia,
You may need to take this to a professional. Electrical problems can be pretty hard to track down even when the car is present. Over the internet it can be most problematic. Do you own a test lamp? Do you have a shop manual with a wiring diagram? If you are to do this successfully, you will need these things at least.
That said, signal lamp switches in earlier Minis are a weak point. You also should check the flasher unit. Beyond these, most lamp circuit problems turn out to be bad connections, especially to ground. I hope I have helped.
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon