Severance offer, what should I ask for? - 10 months and counting

I was offered 4 weeks of severance after 4 years as an IT help-desk technician, and I have a few days to sign. There are 4 people counting on me, so I am trying to be careful. I do not want to leave money on the table. What did you ask for?

Ask for the offer in writing and do not sign on the spot. A day or two to think is normal.

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