Hello Christian, welcome to Beoworld 
You're lucky in that these SP series pickups have replaceable needles, unlike the later B&O pickups. They are not available from B&O anymore, but you might find a replacement stylus on sale, or perhaps a complete pickup on eBay. Or, you can have your current stylus repaired by Axel in Germany (see schallplattennadeln.de).
If you have liked the Beogram and you would still have use for it, I recommend you get it fixed - there are a lot of these on sale, and you wouldn't get very much for it especially without a working pickup.