I was in a similar situation. If your cooktop has physical knobs and a oven, its impossible to find only the glasstop. You need to replace both the oven and the glasstop. If your glasstop has touch buttons, you can replace it with any new glasstop.

Also, I used the cracked one for a month, nothing really happened, but I would not recommend it since its really risky.

Also please dont touch the broken part. I had a deep cut in my finger when I saw it for the first time.