No, it shouldn't last that long. What does the status bar say (bottom right corner of the main TB window? If it was still going I would expect it say "Adding contacts to Google x remaining" with x decreasing occasionally.
Can you do anything in TB or is it frozen? If it isn't frozen then there was an error, so please send me the log and any errors listed under Tools -> Error Console (you can right-click these and click Copy).
Josh