Amending from One Field to Another

I need help figuring out how to add a prefix to an existing description in a project table, generated from the project number.
Here's a sample of my data:

PROJECT NUMBER DESCRIPTION
01200000 Completed Projects
01601530 Steele Sub

I would like the Descriptions to read:
01200000 MO-20 Completed Projects
01601530 MO-60 Steele Sub

The state, “MO,” comes from the first two digits “01” and the coop, “60,” comes from the second two digits. I have a table of a thousand or so projects in an Access database that I need to amend the descriptions of to include these prefixes. Is there a simple way to do this in Access or in Excel without writing code?