If you've never had contacts in gmail you will have to:
1. export your contacts to your sd card. (Go to contacts click the menu button-more-export to sd card)
2. Then you will need to sync your phone to your computer, copy the csv file to your desktop.
3. Open gmail go to contacts and click import contacts and there you have it and they should sync.
You will then have duplicates and will need to delete just the 'phone' contacts