The expansion card can be found if you know where to look. The key is to make sure you pay attention to the part number. Sometimes you can rob them off a PCI model, and sometimes not. I recently picked one up for $20 including shipping.
I would compare a high resolution image of a working 2MB card and compare the positions of the surface mount resistors.
I feel there are two likely scenarios for your card. Either 1MB was disabled at the factory because of a faulty memory chip, or one of the solder joints on a memory chip went bad causing the entire bank to not be detected. In the latter case it shouldn't be too hard to fix if you can reflow the solder joints. Try applying pressure to each cheap (one at a time) and powering the system on to see if you can get the 2nd meg to be recognised. You'll probably have to use a C clamp to help. Just make sure you don't put the clamp directly onto the IC or PCB.
"Will the highways on the internets become more few?" -Gee Dubya
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