What should be my investment strategy?

Recently, due to my wife work, I get a chance to learn those retirement plans. So how should I manage the investment? My fundamental idea is to combine investment and your future life plan. There might be two big decisions. One is when to buy a house and the other is when to go back to China. The two financial risks associated are housing price and exchange rate. I am not expert in either area. But we still can do something to decrease the risk without too much effort.Generally you want to buy a house at low price and come back to China when dollar is strong. But what if the opposite things happen at the time when your decision is made. So at the current time, I put a certain percentage of money into real estate and international stock market. If hourse price goes high and dollar become weaker when I purchase a house and go back to China, it might be offset by the increase in those two funds. Although I cannot perfect hedge that since I cannot put all the investment into those two sources ( currently since I expect subprime loan would drive the housing price down, I put much less money into real estate fund ), it is still worth to do.