At boot time the machine says it has 2 MB.
The Compaq Diagnostic diskette says there is 1 MB on the system board
and 1 MB on the expansion board.

Guess you need the 4 meg expansion board and two of the 4 meg add on boards
to get to 13 meg max.
Didn't find them on the web, best bet to find some would be inside another
deskpro 386s.
If you find just the two daughter cards you would have 10meg max with the 1
meg expansion board you have now.