Buying a home after bankruptcy

I filed Chapt 7 bankruptcy, which was discharged in January 2010, on credit card debt. I did not file bankruptcy on my mortgage and have never missed a mortgage payment. I went through a consumer credit counseling service to apply for the Making Home Affordable Program in March 2010 but my lender (PNC Mortgage) denied saying "You have never missed a payment on your mortgage; therefore, we cannot entertain your request." I want to sell my home at this time because the mortgage payments are high and difficult for me to make due to limited income. I want to purchase a smaller, more affordable home. How long do I have to wait until I can purchase another home? My credit was excellent prior to bankruptcy and I have maintained good credit since. Thank you.