As everyone has said, the first two books on your list should be:
Tang Soo Do Soo Bahk Do Volumes 1 & 2 by Hwang Kee.
your best resource for these, honestly should be e-bay. If you buy directly from the federation, they will cost you over $100 each. Same with most of the independent suppliers. You can sometimes find them on e-bay for much cheaper.
In terms of a bit less expensive books,
Tang Soo Do by Kang Uk Lee Also the same one mentioned by the others. I have used this as a reference for forms many times. It is great because it is compact and has a wide range of forms in it. I can't vouch for accuracy, but there are definately some differences between the history and symbology sections from some other stuff.
Complete Tang Soo Do Manual by Ho Sik Pak This one also has two volumes. The second is for higher belts, but has a lot more history and background. The first one is more basic, obviously. My only complaint with these books are the set-up. They are based solely on the belt requirements for that organization. So you have to figure out at what rank the material you want to learn about it taught at. Pretty affordable though.
History of the Moo Duk Kwan by Hwang Kee This is the Moo Duk Kwan's official take on the history of the organization. Historically a VERY important book. I think it is only available through the federation.
A bit more expensive...
Authentic Tang Soo Do by Chun Sik Kim A GREAT reference all around. Just like all of these, it is written from its organization's perspective, so be careful when you take the stuff back to your school. Expensive though. To get it, you can either try e-bay or the International Tang Soo Do Federation website.
Some things to stay away from....
Young Kil Song's videos....they may be good for whatever organization he's a part of and he is an excellent martial artist, but there are huge differences in his forms from what I have ever seen.
Len Losik....I have never met the guy and he may be a great martial artist, but honestly, I would stay away from any book in which the author cannot spell the name of his art in its native language. His book Tang Soo Do: A Question and Answer Book attempts to write the words "Tang Soo Do" in hangul on the front cover, but in fact, it is just gibberish....a bunch of meaningless symbols. Also, if you look at his publishing history, he seems to be an academic, and I'm sure that academic publications are great....but he has a huge range of martial arts publications on a number of different styles and areas. It is difficult to believe that one man has the background and expertise to publish on so many organizations with whom he is not officially associated (particularly referring to the Moo Duk Kwan (Soo Bahk Do organization)). If anyone has seen any good recommendations on his work, please let me know.
In terms of TSD books, that's about all I know of. There are some more videos and pamphlets out there, but as far as I can tell, these are the "leaders." If you find any other credible, solid sources, please let me know!