Restoring a Snow Leopard time capsule using Leopard DVD boot? possible?
Yes - I'm afraid this is the case. You will need to find a Snow Leopard DVD or Lion recovery HD/USB to restore your files.

Since this DVD used to come with all Macs, you should be able to find a friend who has one. Otherwise, try the Apple store or AppleCare to order a replacement Snow Leopard DVD.