I have dropped my Rollei AFM35 and dam...

Normally you'd have next to no chance: not many AFM35's were made and they mainly appealed to well-off, older, amateur photographers. As a result used ones are rarely for sale and parts donors are as rare as rocking horse droppings. If you do find a parts donor they've likely been dropped damaging the battery cover which as you have discovered is exactly where the camera tends to land.

On the plus side, the cover on this model is a round bayonet type fitting much like the type used on some film SLRs and sometimes on motor drive covers. I don't currently have an AFM35 in my collection but I do have a Canon Sureshot Classic 120 and the battery cover looks like it may well be a functional replacement for your damaged one. As a first point of call visit a camera repairer or a large used film camera outlet to try a few covers for size. if you're in the UK and in the London area then Mr.Cad in Croydon is hard to beat for odd parts like these. I'm confident that you'll find a cover which fits, but you may need to do a little surgery to transplant parts from the old cover to the new to get a functional cover.

Sureshot Classic 120's are fairly easy to find and go very cheaply (£15 or so on auction sites). If you see one in good condition then you've nothing to lose in trying it: even if the cover does not fit you'll discover that the camera originally cost about the same as the Rollei and does pretty much everything the Rollei does. The light metering is highly reliable and the spot metering is superb. I can honestly say that the 38-120mm zoom lens outperforms some of my Leica and Zeiss T* primes and in my opinion is the best lens ever fitted to any compact 35mm which I've owned.

I hope that you've found my suggestions to be of some use and ask only that you return the favour by rating my answer.