I believe you mean iPad 3G.
Yes you can transfer your waypoints to iNavX following these steps
1) I assume you are using a Mac. If so use the LoadMyTracks application to transfer your waypoints to your Mac. A GPX or KML file is fine ..
http://www.cluetrust.com/LoadMyTracks.html
2) Create an account at X-Traverse ..
https://www.x-traverse.com/signup
3) Transfer your GPX or KML file to X-Traverse using the OS X X-Traverse (drag & drop the the file in the X-Traverse application window) ..
http://www.inavx.com/xtraverse.html
4) Start iNavX on your iPad 3G
5) Open any chart
6) Select "Waypoints" tab
7) Select "Import/Export"
8) Select "Account" button and enter your X-Traverse account info
9) Select the KML or GPX file from the list of files
If you don't have a Mac then use some Windows software that can extract the waypoints from your Garmin into a GPX or KML file. You can then visit X-Traverse and upload the file directly to the X-Travere site and then jump to step 4 above.