Actually there are more ways and not so dificult to do, you can efectively get the official rate but you are limited by 3 factors depending what way you take, in almost all the cases the maximun is 1500 usd per month, you can do more but is not so practical, in any case is probably not so easy if you don't have a legal job here and depend on how fast you want to convert them. If you have enough time you can pass your pesos to dollars, but of course you cannot do it from one day to the other and you need to have everything legal.