How to install OS X 10.7 and 10.8 in VMWare Fusion, on a 10.9 host?
If you don't have them in your Purchases in the Mac App store, you can order Lion and Mountain Lion directly from Apple for USD $19.99 each.

http://store.apple.com/us/product/D6106Z/A/os-x-lion
http://store.apple.com/us/product/D6377Z/A/os-x-mountain-lion