For electronic questions like this i would refer to either the user manual or consult a trained and licensed electronics expert, as there are many types, and this is broad.
You can contact Toshiba for a rectory CD replacement. Usually when you are under warranty they would provide you with a free one. If not they would usually sell it at a low price about 25 USD. Heres a tip instead you should try eBay. Do a search with your computer model + recovery Cds and they should be cheaper
The only truely trustable source for recovery cd's is the original manufacturer. While they mage charge a substantial amount of money, it is the safest, easiest, and cleanest option available.