Double check the end. Is it USB or PS2? (or both because of adapter)
If it is PS2 then adapter like
this one will make it match up. This is just an example, so besure before you buy.
I did the same thing with iGPS 360, it came with USB cable, but you able to unplug the cable from the unit. I then bought a X50(v)/X51(v) cable to connect to my unit. Could of also bought a CF adapter or BlueTooth Shoe. So just look around a play little with Google.
EDIT: Also do not be to attached just in case. You will still need software and Maps and will run about $100, if you look at
buygpsnow.com or other sites, you can get the software/maps and gps for the $140 - $160 range (including discounts). So it is NOT always nessary to reuse what you got, because cables will run around $20 with s/h and new is another $20 to $40 dollars in a bundle.