It's illegal for a vet to prescribe medication without actually seeing the cat. If you have a relationship with a vet and he has confidance in your diagnostic abilities, you may be able to get him to phone something in to a pharmacy for you.
The only treatment that I can advise at home is irrigation with a peroxide or betadine solution. Then apply some neosporin ointment.
Puncture wounds typically require a drain, as I'm sure you're aware.
Let me know if you need more help.