While UWZ is the most recent edition, other editions will have the Ras army list. If you have access to the Warzone boxed set, the booklets Rules of War (main rules) and Forces of War (army lists) are all you need. If you are able to find the first editions, the books Warzone (main rules) and Dark Eden are what you would require.
Search Ebay or any other stores, they may have copies going at reduced prices.
Jase