Severance offer, what should I ask for? - 9 months and counting

I was offered 11 weeks of severance after 11 years as a call-centre agent, and I have a few days to sign. There are 11 people counting on me, so I am trying to be careful. I do not want to leave money on the table. Did anyone negotiate and succeed?

Read the release carefully. Mine included things I did not expect, like a non-compete.