In my experience, a lot girls will cut out most of the drinking and will dress more modestly once they are in a relationship with you; provided they value the relationship, are not party girls, and are not being constantly pressured to do so. Your are correct, in that a lot of women do drink, however, depending on where you are meeting these single women (clubs, bars, and at college), they may not be representative of whole population’s behavior. However...
Now I not sure about the Islamic faith, but I know that in the Christian faith, you are warned about being “unequally yoked”. This just means that if you are Christian, you will have a much easier time keeping to the Christian values (and so will your partner) if you are in a relationship with another Christian. This would be the same with your faith. Plus, while women will change some, many will never reach total abstinence from alcohol or complete modesty: people rarely change that much.
So yes, if you wish to date girls that drink and such, you’re going to have to be the “Rogue”; or you could screen out girls that engage in those behaviors, reducing your dating pool size but allowing access to girls who you don’t have to rely on changing themselves.