I am planning to buy a house or a condominium in Northern Virginia Area. Do you guys have link to some good realtors. Do you suggest me to buy single family house, town house or condo? I am doing this mainly for investment purpose and utilizing my apartment rent to some investment. Is this the right time to buy? 

Is this the right time to buy?
Sure, but I don't think price will go up in a while. Norther VA, like any other DC metro area market, hasn't seen the values go down like other parts of the country. Buying a house in VA could cost serious money. They say when real estate goes up, House is the first thing to go up followed by town house and condo. When it crashes, condo is the first thing to go down followed by a town house then house. So, a house might be a good option in surface. However, because of the associated cost, it might not be a bad idea to invest in a condo or town house. It really depends upon how fat your wallet is (these days you gotta cough up a lot of downpayment to secure a mortgage) and how much risk are you willing to take.

 Any Idea about the minimum credit score required ? Aren't there any realtor among sajha members ?