Is it the
Leadtek 9531 as shown here? If so, you can either upgrade to Destinator 2 for the quoted $50.
On the subject of SiRF & NMEA. All GPS receivers can output NMEA, whilst only receivers using the Sirf chipset can output to Sirf. Nearly all Sirf receivers can also be switched between the NMEA or Sirf output, all it takes is a software utility. Leadtek provide two for their receivers, one's called CE Monitor, see the instructions and download link
here.. I can't get the link to work at the moment, but it might work later.
The other is Winfast Navigator, see instructions and a download link
here. It comes in PC and WinCE versions.