My stimulus check says $398.00 and I filed as head of household and have one child. Is this correct?

I claim 0 on my exemptions on my W-2. I claimed one child on my 2007 taxes. My stimulus check that is supposed to hit tomorrow is showing $398.00. Does this seem correct? I am not understanding. I thought that it should at least be $600. At least $300 for me and $300 for my child.