Help on background checking in

We submitted our medical examination, police certificate at the beginning of June, 2004, and paid landing fee in the middle of June. At the same time we were asked for submiting background checking form . We submitted all documents including background check form in the middle of June. We didn´t get any response from buffalo since then. So at the end of september, I wrote a letter to buffalo asking about our application status, and I got a letter from them today, said that they are waiting for the results of the background check, but didn´t say how long it will take. So I am wondering if there are someone have the same experience, and have idea about how long it´s going to take to get the result of background check. I am worried about whole process, afraid that I am going to wait for another year or longer. Your response is appreciated. Thanks.