Are they networked? If so, you can probably connect to the Wallstreet via the eMac and copy files that way. Or you can get a PC card with a firewire port, stick it into the Wallstreet and transfer that way. At least I think that would work, sorry, I'm not 100% sure. I'm guessing you're not running OS X on the Wallstreet?
Here's what I would do: Have someone remove the IDE harddrive from the Wallstreet and put it in a USB (or firewire) external harddrive bay by using a 2.5 IDE to 3.5 IDE adapter. Then plug it into your eMac.