Concerning Call of duty 5 for pc? (This is pretty complicated so I guess i don't really expect a good answer)?

So I just bought Call of duty 5: World at War for my PC because I really wanted to play Der Riese Again with out blowing $150 on the special edition black ops, but when I got it I realized I couldn't find the DLC for PC anywhere. but after about an hour of searching I found out that the extra maps come from the patches. So I just searched for the most recent patch, which was v1.6 but after the hour and a half it took to download that i tried to install it and it said i needed to have v1.5 first, so i downloaded that 600mb file and then when i tried to install that it said it couldn't find a valid copy of world at war on my PC, but I just bought it new. Anyway I was just thinking, do i have to download and install ALL of the patches to get this to work, or is there a way I can just download der riese OR if there's just one big file i can download with all the patches in it. If you can include a link that would be great! thanks in advance for anyone who tries to answer, just so I can play this one zombie map lol.