Are you planning on inputting them manually?
Another option might be to find a data cable that (I think) may power it from the USB on your confuser, then download yourself a coopy of EasyGPS ( http://www.easygps.com/download.asp
) and you can input them at leisure - and a LOT more easily - then with about 2 clicks squirt them all down the wire into the Garmin.
think for most garmin sets you can buy "power only" "data only" & various other combinations of leads & plugs / sockets for them. I bought a "Power & data to bare tails" that I installed on the boat to get it to feed the VHF in an emergency.