Start asking everybody you can think of whom whom he or she knows who might be interested. If they can't think of anybody, ask them whether they can think of someone else who might know.

You can read a lot of information on finding investors in the United States, but you know full well that Argentina is a totally different market, so you have to look there.

What about http://www.inversiones.gov.ar/, which looks like a government site about attracting investors? I found it by searching for "agencia desarrollo argentino" in Google. Look at the links there.

Look locally; you'll have way too many hurdles to jump if you try to sell not just your idea, your business plan and your team but also the idea of Argentina as well.