Congrats on apparently making a clean break from the Ecuador situation. Sounds like the $600 for agency fees was what you were sending that chica in a couple months, so you should be banking good for this trip compared to if you started sending $$$ to her again.
Do these agencies give you profiles of women they have 'on file' beforehand and allow you to make contact? If so, as well as using other methods, I'd suggest you start making notes, perhaps literally on paper, of women you meet between now and November.
I'd make at least two columns, one that simply rates their physical appeal and another that might be more detailed, but ends up with a 1 to 10 number, rating their personality--characteristics such as general compatibility, how straightforward and honest they appear to be--how beaten down by life and previous BFs they might be and so on.
Just on-line, you can meet a lot of women you might end up meeting there, so you might as well start the process of elimination now. Hopefully you can meet the best prospects. There's always a good chance that in the first few, one's going to come on real strong and try and stop you (or else) from seeing other women and you only have 12 days, so make them count.
Remember, the hottest ones typically have higher mileage, are higher maintenance and I wouldn't weigh their personality characteristics too lightly if you want someone long term. Not saying go pick some ugly girl, but again remember this is hopefully for the long haul and once to fly her back home, if she's half way decent in Bogota, she's gonna be a smoker back home.
Think about the lyrics of the Artic Monkey's tune "I bet you look good on the dance floor" and run from that kinda babe! A little paranoia when looking for a woman is a good thing!
