In reply to breed: The climb season to PEru/Bolívia is june to september. After that rain/snow are very frequently and you probably will have problems to arrive base camps and acumulate snow. In the patagonia and south Andes, like Aconcágua, the season goes dec to march. The north patagonia is very big , but the deserts begins after Aconcágua.
I don´t know your climb experience, but I suggest the lakes region of Chile. There is a lot of places to go, major of that beatifuls Vulcans circulated by lakes and trees, Like Villarica (the most popular), Lanin, quetrupilán (I think write this way), and many others in the region of Bariloche (Argentina). Try a look to this places.
In the Aconcágua region, there is many others, like Cerro Plata and Mercedario. But are more highest than the south Vulcans, with long time climb.