EEOC CLAIM - What to do next?

In October of 2010, I began working for a local bank. It is small in size and all of the employees had been working together for 3 or more years. When I started my job, I immediately realized how unprofessional the employees were. They consistently poked fun at different elasticities, religions, and disabled people. I had spoken with my co-workers individually at first to address the discomfort I felt being around their conversations - this upset the group a lot. One of the people in particular began poking fun at me. I am a white woman with a biracial child. My son is also half black. The people I work with know this about my family. The man that I worked with, would imitate uneducated southern black people, and pretend that he was a slave when asked to do something. When I spoke with the Branch Manager, it went unaddressed. I took my complaint to the next level and spoke with our District Manager, who also had no effect on the group. During a company party, while my branch members were seated together for dinner, the topic of confederacy was brought up - in which my co-worker announced to the entire table that "blacks need to be re-slaved anyway". The entire table laughed - until I announced how upset that remark caused me. My Manager proceeded to call me a "kill-joy" - needless to say, I handed in my resignation letter the following business day - but where do I go from here??