Savannah Peach Cheesecake

• 7 sugar substitute
• 2 peaches (fresh)
• 1 gelatin (envelope unflavored)
• 450 ml peach lowfat yogurt
• 230 gr graham craker crumbs
• 120 ml skim milk
• 120 ml water (cold)
• 230 ml cream cheese (light)
• 65 gr sugar
• 40 gr margarine