My girlfriend has recently been given a 1970's original OM-2. I have been reading up about prices but I don't know if these are for original or reissues. I do not know a lot about cameras I will admit that now but I was wondering if you could give me advice on two points

1. How much do you think this camera would be worth. It is in perfect condition and looks barely used (a rough estimate would do)
2. The camera unfortunately has a broken film advance lever it seems to be stuck. When we put new batteries in it it signalled it was still responding to the batteries as the exposure counter showed and the red lamp came on. I was wondering if anyone would know how much it would cost to fix

Thank you for reading and your time!