Traveling to Colombia

Hey guys I have a question since I am going to Colombia the end of this week: what way would you recommend to convert currency from US dollars to Colombian Pesos?

I know that the bank and airport are bad ideas hence I was thinking of something like western union.

Also since I am going to go there for a week, I was thinking about bringing a set amount of money ($700-$1000) but I don't know how much I 'need' considering that Colombia is cheap and the peso keeps going up from recent exchange...

Traveling to Colombia