There is so much lore surrounding breast feeding and alcohol consumption and very little actual research to back it up. I actually work for the woman who has done most of the research that is out there on the issue. A few things we do know for sure:
1-The alcohol content in the milk peaks around 1 hour after you drink-interestingly because breast feeding is so metabolically demanding you metabolize alcohol completely differently when you are lactating compared to when you aren't.
2-It take 3-4 hours to completely clear your milk.
3-The baby can actually tell the difference in your milk, in fact most babies won't eat much if the mom has just had a lot to drink.
4-Making a habit of drinking while nursing causes your baby to get used to the taste and eventually they learn to like it, most experts think this makes them more likely to become alcoholics as adults.
5-The test strips can tell you how much alcohol is in your milk, but they can't tell you about the breakdown products, which are the part that is actually toxic and we don't know anything about how much of those compounds are in your milk and how quickly they are cleared.
6-Drinking does NOT increase your milk supply. In fact the opposite is true.
All that being said, I did drink on occasion when I was breastfeeding. I'm not sure how old your child is, but I waited until my son slept for a solid 5-6 hours and then I knew I had a window in which to have a glass of wine and not feel bad about it.
Most of what I listed above is discussed in more detail here: http://pubs.niaaa.nih.gov/publications/arh25-3/230-234.htm
Just wanted to say I'm not trying to judge anyone on their decision, I just think everyone has a right to be informed as much as possible about the decision they are making.
Updated-I didn't realize that the question of supply wasn't discussed in the link I originally posted, but you can find it here: http://www.medicalnewstoday.com/releases/22437.php
@Tori, everyone can list exceptions to the rule, I'm just providing the evidence that for most people it isn't true that alcohol will increase your supply. I also was not saying that a drink would turn your child into an alcoholic, clearly that is ridiculous.