For your problemCheck out the datasheet, probably you have to convert the data.
A while ago I saw some tutorials about bad GPS antennas, try googling a bit =)
For converting back to serial (in case someone just landed on this page with Google :p)
TemporaryTry hooking up an FT232 breakout board or something that does the same job. (you can mirror/echo them with your PC) That should work I guess.
PermanentIn my opinion, an acceptable permanent solution, is any microcontroller with USB built in.
Something like PSoC5 is quite easy to program and should do the job.
The advantage of using a microcontroller is that it's smaller, more efficient and cheaper.
Note that USB usually is a lot quicker than UART of course.
I could mod it where I can tap into the TX pin before it gets converted but I want to avoid this. Thanks.
Still, you really are turning water into wine and trying to get the water back....