If it is not your first one, then get one of those kits at the pharmacy- they have suppositories and creams, I like the three day cream, but you can ask the pharmacist which they recommend. If it is your first yeast infection go to a doctor and get it diagnosed.
The best treatment, for me, is Diflucan. That requires a prescription. Good news, is that if you have been treated before, alot of times the dr will just call it in for you. There are some great preventative measures that have worked for me, but once it's there I must have Diflucan to get rid of it. Don't mess with those OTC, you can spend a lot of money and it still isn't gone. Might as well go for the good stuff. Good luck!