The easiest method of finding this information is to contact your Realtor and ask them to provide you with sold data for the addresses in question. You should also be able to check your county website to ascertain the sales price. In some states/ counties you may not be able to procure as much information as in others.
I would highly advise finding a buyer's agent to assist in your purchase. Some might argue that the benefit of using a buyer's agent increases as the market slows down. As a current Realtor and a former home buyer, a good buyer's agent is worth their weight in gold.
Good luck -