The online manual includes advice how to transfer files. HFVExplorer v.1.3.1 has also limited support for ZIP media.
To connect the SE/30 to your new iMac is not easy, except the SE/30 has got an ethernet network adapter (and if it has got a network adapter, the problem to transfer some extra software to the old Mac in the first place might remain, still).
Consider to ask a local Mac dealer or user (group) in your environment to provide the floppy disk you need. In case they refuse to help, p.m.