Ludvig Von Mises was a brilliant man. And it is a pleasure to see his mind at work. That said, his writing is dense and his terminology is his own - at least to a degree. So reading "Human Action" is not a small project (you can download a pdf of the book on the internet, free - and I think at that Institute you mentioned). You'll have to decide if you want to make that investment of time.
Another tome that is very much in tune with Objectivism is Capitalism by George Reisman. Also a very large book, but a bit more readable. Human Action is a classic, and it will take some time to see if Reisman's work gains that stature. It can be downloaded for free from Reisman's web site.
Might I presume that a philosophy of economics that's founded upon Rational Egoism might be found in ''Unknown Ideal' as suggested reading by Luke? Yes. It is a collection of essays by Rand (and a few by Nathaniel Branden, Alan Greenspan, and others) - it is not a book on economics, but on the moral foundation that economics must rest upon. It takes on many of the arguments against capitalism - from a moral perspective. It is a bit dated - 1966 - but it is well worth reading - and it is a very quick read. Some people, particularly with time in academic harness are strongly put off by her style of presentation and consider it harsh... I love it, but that's me.
Eva, I admire your quickness of thought and the range of your thinking (even though we might not agree in many areas). I suspect that if you keep looking at the foundations of whole disciplines, like economics, while casting a sharp eye on the implied ethical base, and the implied epistemological principles you will sort things out in ways that set you apart from the cookie cutter 'thinking' we often see (especially in most Progressives and Conservatives). If you want to read a solid and bold presentation of a philosophy for psychology, read the first half of Nathaniel Branden's Psychology of Self-Esteem. I mention all of this because I don't think I'll ever have much respect for thinking that doesn't integrate logically with some philosophical base - floating abstractions might be fine for daydreaming, but not for something I want to take in make a permanent part of my world view.
Most people would not do well with the following recommendation, but you might. It is a very small book, but dense, and for me anyway, stunning. Ayn Rand's Introduction to Objectivist Epistemology.
I suspect that if you read some of Rand's non-fiction (Capitalism, Selfishness, and Intro to Obj. Epistemology) you'd be in a better position to know whether there is anything of value for you in a forum like this. Here, what we have for the most part, are people who are digging deeper into those basic principles (e.g., rational egoism vs altruism) and about the application to real world situations. You can also look at the short, but very well done articles on individual concepts that are the core of Objectivism: Objectivism 101. They were written by the owner of this site, Joe Rowlands.