First off I'm not sure if you were joking with "the gringo is always expected to pay" bit, but Ive found quite the opposite. In fact, when I had my first asado, the argies were fighting with me because I didnt want to charge them (didnt know that its pretty customary to have everyone split the cost when you have friends over), since that's how we do it in the states, given that your friends will most likely have you over for dinner.
And second, maybe my problem has been that I was trying to get someone my age. But based on your advice, I'll have to start giving some more attention to the 10 year old consortium.
But seriously, I'm not saying I'm a natural Don Juan, but it's really a bit exaggerated when EVERYONE tells you "all you have to do is speak english and the girls will come flocking". Not to mention the original poster doesn't seem to be trying to pick up chicks at the bar haha