Should I negotiate my severance? - 11 weeks in

The company sent a severance agreement with a release of claims, and I am unsure what to do. I worked as a data-entry clerk before this. I do not want to leave money on the table. Did anyone negotiate and succeed?

I asked for two more weeks and a neutral reference. They agreed to the reference and added a week.

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