According to a Google search the main device specifications are...
WinCE 4.2
32MB RAM
320x240 Resolution
SD card 2GB max (Not SDHC)
And comes with iGO 2006 installed.
The low RAM will prevent you from running any of the latest navigation applications, But a minimal build of iGO 8.3 should work.Use another SD card and download a copy of iGO 8.3 to it, Make sure the path to the new app (folder\filename.exe) is the same as it is on the original card.
EDIT: Chas beat me to it