Illampu looks most likely but it's IN Bolivia rather that near to it. As indeed is practically everything east of Titicaca since the border bisects it.
Illampu Mountain
Illampu is the fourth highest mountain in Bolivia. It is located in the northern section of the Cordillera Real, part of the Andes, east of Lake Titicaca. It lies just north of the slightly higher Janq'u Uma, near the town of Sorata. Wikipedia