one word: Diflucan.
It treats a yeast infection effectively in 24 hours and it's just one tiny pill you take. It's presciption only though. You should go to the doctor anyway and get properly diagnosed.
Are you absolutely sure that it is a yeast infection? Have you been diagnosed by a doctor before for this and know for sure that it is yeast? If you are sure, the Monistat 7 day treatment is usually helful in clearing them up. The 1 day and 3 day treatments are not usually as effective.