You do realize that a new machine cannot run old OS software? An older machine can run newer OS's to some limit. Check if your machine will run each version of the OS.
Apple may still supply the original restore CDs/DVDs for a nominal fee. Have your serial number and model information available when you call them.
AppleCare Support Phone Number: 1-800-275-2273
open 6am to 6pm Pacific Time
Apple Phone Sales 1-800-692-7753
International Technical Support Numbers
"You have to call Apple & likely ask for a Product Specialist to get it (Leopard), if they still have it... helps if you tell them you have a new iPhone (iPad) that needs it!"