How did local, indian, and chinese elements and influences interact o help shape the societies of early Southwest Asia? Were southwest Asian cultures really unique, or were they largely based upon those of India and/or China?
Google Books is a helpful place to begin research on this kind of topic. Not only will Google Books lead you to books relevant to your topic, but those books themselves will often contain references to (and discussions of) other relevant books. It's also useful to search Amazon.com's book section; the search engine at Amazon often nicely complements the one at Google Books. If you have an Amazon.com account (which is free, and which is easy to set up), you can often search inside books, just as you can often do through Google Books. Here, in any case, is what I found when I did a Google Books search of your topic:
The history of cultural interactions is one that is absolutely fascinating and something that we are forced to see the importance of today. You might like to consider the way in which cultural interactions produce hybridity, or a mixture of elements of both. Certainly this can be seen in the way in which Indian and Chinese cultural norms were incorporated into the fabric of new states.
I think you mean Southeast Asia, not Southwest. At any rate, outside influence and local ways mixed in SE Asia. For example, when states first developed in SE Asia, they borrowed Indian and Chinese models but adapted them to local circumstances. As an example of borrowing, Vietnam borrowed state Confucianism and called their rulers emperors. At the same time, rulers like those of the Angkor tried to meld Indian gods with local deities.
So, they were based on India and China but they were still unique because of the local influences that were mixed in.