In a medium saucepan, combine 1 cup sugar and 2 cups water. Bring to a simmer, and cook, stirring occasionally, until sugar has dissolved. Add lemon juice and peaches. Simmer until peaches are tender when pierced with the tip of a knife, about 10 minutes. Remove from heat, and let stand until room temperature. Carefully remove skins from peaches, and discard. Transfer to a bowl, and refrigerate until chilled.
Place raspberries in a fine sieve set over a small bowl. Using a rubber spatula, pressing on the raspberries to extract as much juice as possible; discarding solids. Add remaining 2 tablespoons sugar to raspberry juice, and stir until the sugar is dissolved. Serve chilled peaches with vanilla ice cream and raspberry sauce.