Topic: What is my priority date? F4

Hello, My brother filled I-130 in December, 2008 for me. He received I-797C with Received date "January 06, 2009" and Notice Date "January 08, 2009", but no priority date (blank). I have checked on USCIS site for the application status. It shows "On January 11, 2010, we received your Form I-130, Petition for Alien Relative, Receipt Number EACxxxxxxxxxx, at your local office." Which one is my priority date? Thanks in advance.