Older Garmin devices only receive traffic via a 'sideband' of an FM radio frequency. Modern devices with HD traffic (DAB+ in UK, EU, AU etc., Digital Radio in NA) seems to get faster and more reliable updates. Unfortunately in some places the FM info is horribly delayed so sorry but 'you get what you get' and it's unlikely related to the main system software (firmware) but you should update it to V2.80 anyway.

GVN60 indeed updates from an SD card as you've described. The instructions from Garmin as as follows:
  1. Create a 'garmin' folder on the SD data card (must be at least 100MB of space available on the card).
  2. Download the appropriate self-extracting archive file onto your hard drive.
  3. Run the downloaded executable file.
  4. Click on Browse and select the SD card reader in the list, then select the 'garmin' folder.
  5. Click Unzip to save the files onto the 'garmin' directory on the SD card.
  6. Wait for the message that the update was unzipped successfully and close the updater.
  7. Safely remove SD card from PC.
  8. Insert SD card into GVN60 KW EU. If there is already a card inserted, temporarily remove it.
  9. The update will begin automatically after few minutes and then last for 3~5 minutes. It will probably show 'no navigation' on the screen during the update process. Please do not power off unit while the update is in progress. When finished you can verify the update by checking the version number in Settings->Device->About.
  10. Remove SD card used for software update and reinsert other card if necessary.

Note that it may take a few minutes for the firmware update file to be even recognized before the update can start. If it's still not updating to V2.80 then check that the SD has only a Garmin folder on it, nothing else. Check that the only file inside it is a file named GUPDATE.GCD and that it's size is 84.8 MB (88,995,435 bytes).

You might get further software updates by using GarminExpress after following the instructions in this link:
Code:
Please Login or Register to see the links
Maybe other updates via GE will include a traffic-specific software update.