The fact you asked about losing your license if you re-install Mach3 tells me you probably haven't got your license file backed up somewhere safe. Your license file is in the main Mach3 directory. I'd copy and paste it to some other locations (including places other than that PC).
Likewise back up your profiles and any custom macros you have.
Then if re-installing Mach3 ever does cause a loss you just paste them back in.
Regarding the card you have coming. It sounds like it's a combined parallel/serial card. I'm sure I heard it recommended somewhere to used a dedicated parallel port card for Mach3, not a mixed one. I repeat though, that's just something I heard.