Severance offer, what should I ask for? - 7 months and counting

My manager said the package is final, but the letter gives me time to review. I have read a lot of threads here and could not find my exact situation. I do not want to leave money on the table.

Thanks for writing this out. I went through something close to it 7 months ago, and it settled down once I kept a simple log of every call and form.