Lets say I have
class Person
{
public Person(int age, string name)
{
Age = age;
Name = name;
}
public int Age{get;set}
ClassInstance.GetType.GetProperties() will get you your list of PropertyInfo objects. Spin through the PropertyInfos checking PropertyInfo.Name against propName. If they're equal then call the GetValue method of the PropertyInfo class to get its value.
http://msdn.microsoft.com/en-us/library/system.reflection.propertyinfo.aspx