Ayn Rand believed that a free market economy in which people provided for their own survivals was best for the societies of the time in which she lived. I suspect she would continue to believe such a system is best today.
The current difficulties with the American economy have sources that are complex and numerous. It would be a mistake to declare that the reason why the economy went south is simply because corporate executives behaved fraudulently (though clearly they did). However, to the extent fraud was involved in their behavior, I would point out that laws against fraud were favored by Rand. I suspect she would point that out and claim that she is still right in her preference for a non-fraudulent capitalistic free market economy.
It should be noted that capitalism (of a degree) has existed in this country for more than two centuries. Thus when you say "since capitalism cannot exist, whatever form of capitalism a country concocts is never going to work," I raise my eyebrows with surprise. Clearly, it has worked in this nation for quite some time. Now, plainly you are correct to indicate that some regulation is needed in government. Rand herself indicated that proper government intervention into the economy is a good thing. She merely limited the extent of this proper intervention to the prevention of fraud and the preservation of property rights. Recent events suggest that regulations in place to prevent fraud were ineffective, but the principle of a free market economy with limited regulation is still one that is easy to defend and justify.
Rand's arguments on the subject of altruism are well-known and, unfortunately, far too lengthy for this answer. Indeed, I think that running an economy based on altruistic principles leads to problems of another sort (though equally fraudulent). We see this is in this country with fraudulent welfare and disability claims that cost taxpayers money. And, of course, under Rand's philosophy, we are not our brothers' keepers, so when you refer to people who are "interested in the betterment of the world and its people," she would indicate that the best way to better the world in which you live is to better yourself. Already, as our government deems itself responsible for the allocation of societal resources, we are seeing people vote only in accordance with the candidate who promises them the most. These people are not to be blamed for doing so, but it is unfortunate that government is so involved that legislative edict, and not individual merit, is becoming vastly more responsible for the allocations of resources in our society.
As to your philosophical recommendation, for my part, when I hear "altruism," I think socialism. I think of a world in which a strong central government will tell me where to go to school (and what I can study), what career I will pursue, where I will live, what food I will eat, etc. I think of the bread lines in the former Soviet Union, the greatest socialist power of all-time and a testament to why socialism is ill-conceived. And then, of course, I come full circle and think of Rand, a woman who fled that environment for greener pastures in America and who dedicated her life to espousing a philosophy designed to make sure the mistake of the Soviet Union would not be duplicated.
You raise an interesting question. Your thoughts on socialism, though I disagree with them, warrant the consideration of anyone who reads it. However, in choosing socialism, consider the problems that will arise then. It is insufficient to say times are hard, so capitalism is failing, so let's become a socialist nation. These are changes that require a consideration of issues that go unmentioned in your commentary. This being the case, I'll invite you to consider things further. Perhaps you will continue to believe the same way you did when you typed up the question. Perhaps you'll change your feelings (and there's never anything wrong with that). However, in any event, I suspect you would find that Rand would not share your views, so to the extent your inquiry was geared in that direction, there's your answer.