There's 2 authorized distributors I know of down here, ICON and iOne, both with multiple locations, so best to exhaust those options because the only other way if you have OS X 10.5 is to order Snow Leopard online from the states.
Yea, iCon (Industrias de Computacion Nacional) was the first authorized distributor but not the only one. iOne is a newer one, they're in Avenida Escazu (where the IMAX theatre is) among other locations. Hopefully they got a Snow Leopard package so you can upgrade from there!